It's helpful to understand just how colonial enterprises have worked over the past two or three hundred years. A fairly succinct statement can be found at wikipedia:
The colonial period normally refers to a period of history from the late 15th to the 20th century when European nation states established colonies on other continents. During this time, the justifications for colonialism included various factors such as the profits to be made, the expansion of the power of the metropole and various religious and political beliefs.
Note the key elements - a colonizer, placing its people in the colonized territory to rule over it and extract profits and resources. This was certainly the pattern when the British created their colonies in America, the Caribbean, India, and throughout Asia. It was also a pattern for the French in North Africa and the Caribbean, and for Belgium in Africa. In each case, the colonizing power didn't just send its people over to the colonized territory. It put them there to rule on its behalf. The key phrase is "on its behalf."
For example, British rule over India began with the East India Company establishing a commercial foothold in India in the early 18th century, which eventually grew into governmental administration and a military presence that was private, but had the blessing and overall protection of the British government. The presence of the East India Company led to the eventual assertion of direct British governmental control (the Raj) over India in the mid-19th century.
In the Congo, the Belgians ruled directly almost from the start. Under King Leopold II, Belgium plundered the Congo for its resources, in particular copper and rubber, generating enormous profits for Belgium. The Congo became an official colony of Belgium in 1908, with an explicit Belgian governing administration.
Israel clearly doesn't fit that pattern. When I hear someone say that Israel is a colonial enterprise of the West, the first question that comes to mind is, who is the colonizing power? It clearly wasn't Britain. Sure, Lord Balfour, the British Foreign Secretary, declared in 1917 that:
"His Majesty's government view with favour the establishment in Palestine of a national home for the Jewish people, and will use their best endeavours to facilitate the achievement of this object...."
However, the British did very little to encourage the actual creation of that Jewish homeland, and from 1935 on, the British actively tried to prevent Jewish refugees from the Holocaust from reaching Palestine. For example, Jewish immigration from 1919 to 1941 hit a peak of 66,472 in 1935, but the British informed the Jewish Agency that only a third of its requested quota for 1936 would be allowed to enter Palestine. Consequently, as the Nazi's genocide of the Jews began to pick up speed in Germany, the British only allowed 29,595 Jews into Palestine in 1936. And in 1937, the number dropped even more drastically, to 10,629.
After World War II, the British were no more generous with respect to immigration of Jewish refugees:
On June 6, 1946, President Truman urged the British government to relieve the suffering of the Jews confined to displaced persons camps in Europe by immediately accepting 100,000 Jewish immigrants. Britain's Foreign Minister, Ernest Bevin, replied sarcastically that the United States wanted displaced Jews to immigrate to Palestine "because they did not want too many of them in New York."
Most of the Jews that reached Palestine between 1945 and 1948 came illegally, and when caught by the British, were put in detention camps on Cyprus. The British detained approximately 50,000 Jewish refugees who tried to enter Palestine illegally.
It's also important to note that the overwhelming majority of these Jewish refugees trying to enter Palestine were not British. Rather, they were of every European nationality - French, German, Polish, Hungarian, Bulgarian, Russian, etc.
Consequently, it would be absurd to claim that Israel was a colonial outpost of Britain, the only nation that had any governmental authority over the region during the years leading up to Israel's creation. It would be just as absurd, if not more, to claim that Israel was a colonial outpost of any other European nation. Germany had just finished trying to slaughter the Jews of Europe. And none of the European nations had any warm, fuzzy feelings for Jews. They just wanted the Jews gone from Europe, and had no interest in sponsoring Israel as a colonial outpost. Probably the largest source of European immigrants to Israel was the Soviet Union and its satellites in Eastern Europe. It would be ludicrous, however, to claim that Israel was a colonial outpost of the Soviet Union. The reality was that the Soviet Union was busy persecuting its Jews, and simultaneously backing the very Arab states that were so hostile to Israel.
It's also useful to take a look at the Israeli population and how it changed after the founding of Israel. Between 1948 and 1995, only 71,480 Americans immigrated to Israel. Only 26,000 came from the UK. By contrast, between 800,000 and 1 million Jews came from Arab and non-Arab Muslim countries between 1948 and the early 1970s. These were the Jews who were ethnically cleansed by the Arab and Muslim nations following the creation of Israel - stripped of their lands and property, deprived of jobs, and expelled either overtly or implicitly. They weren't the Ashkenazim of Europe, they were Mizrahim and Sephardim. They didn't speak English, or French, or German, or Russian, or even Yiddish or Hebrew. They spoke Arabic or Farsi. By 2002, almost half of Israel's population had its origin in Arab or non-Arab Muslim countries. But you never see the Israel-critics on the left mentioning this Arab/Muslim ethnic-cleansing of the Jews, nor does anyone assert that Israel, by its population, might be a colonial outpost of the Arab/Muslim nations.
Consequently, Israel doesn't even come close to fitting the traditional notion of colonialism - a nation sending its citizens into another region to establish a base of power. If Israel is a colonial outpost, it is one without a colonizer.
Perhaps when someone on the loony left makes the assertion that Israel is a western colonial enterprise, they mean that it represents "white Europeans" going into a region that is neither white nor European, and asserting power over the indigenous brown people. Quite often I've seen comments on Democratic and liberal blogs about how Israelis are "white" and the Palestinians are "brown." Of course, anyone who makes such a comment is woefully uninformed, and has probably never seen an Israeli or a Palestinian, for that matter. As I noted about, nearly half the population of Israel are refugees (or the descendants of refugees) from Arab and non-Arab Muslim countries. That would make them kind of brown, too.
What people really mean when they refer to Israel as being a colonial outpost is that Israel is a colonial outpost of the United States. In holding that belief, however, they show an alarming ignorance of the history of US-Israeli relations. Between 1948 and 1968, Israel and the United States simply weren't very close, diplomatically or otherwise. President Truman provided diplomatic support for the founding of Israel, but refused to supply the new state with weaponry to defend itself in the War of Independence. Indeed, it was 14 years before the US provided any serious military aid to Israel, when the Kennedy Administration sold Israel the HAWK anti-aircraft missile system.
The primary supplier of weaponry to Israel between 1948 and 1968 was France. Israel destroyed the Egyptian air force in the Six Day War using French fighter jets and bombers, not US aircraft. The US didn't start providing serious military assistance to Israel until 1968. And of course, when the Egypt closed the Suez Canal to Israeli shipping in violation of international law in 1956, Israel attacked with the backing of England and France. The United States joined with the Soviet Union in forcing Israel to withdraw from the Sinai. Hardly what you would expect from the colonial master. And as I have pointed out above, between 1948 and 1995, only 71,000 Americans immigrated to Israel.
Since 1968, the relationship between Israel and the United States has certainly been a close one in every sense of the word, but can one really say (with a straight face and a shred of honesty) that Israel is a colony of the United States? If it is a colony, you'd think it would do our bidding, at least some of the time. In truth, however, Israel does what the US wants when it suits Israel to do so, which isn't that frequently. If the US really called all the shots the way the colonialism adherents believe, would the West Bank settlements still exist?
So for all those who spout idiotic slogans about Israel and colonialism, don't quit your day jobs. Put away your textbook from Marxist Theory and Imperialism 101, and learn about the history of the region.