Oh lordy, that website is very good at scaremongering isn't it?
Colin T. Campbell's casein-fed rats again, Chris Masterjohn addressed this study
and there's more than meets the eye:
In the very paper (2) that Campbell cites as "a revelation to die for," showing that a high-protein diet turns the cancer switch to the "on" position, the low-protein diet proved lethal to the animals. The investigators gave rats a small dose of aflatoxin every day for six months and fed them either a 5 percent casein or 20 percent casein diet. The experiment carried on for two years, in fact, but they stopped adminstering aflatoxin at six months for the simple reason that half the animals on the low-protein diet had died. They had typical symptoms of aflatoxin toxicity including liver necrosis (cell death), proliferation of bile duct tissue, and fatty liver.
All the animals receiving 20 percent casein, on the other hand, were still alive at that point. For the remainder of the two years, the rats receiving 20 percent casein continued to live longer, but many of them developed liver cancer or pre-cancerous changes, while none of the rats fed 5 percent casein developed liver cancer.
So there's an easy way to prevent cancer, make sure you die before you get it.
Regarding the diabetes, it is true that many T1 diabetics exhibit antibodies to casein, but that makes sense when you remember that diabetes is an auto-immune condition and allergies are often expression of auto-immune dysfunction. The two go hand in hand. That's like saying that just because Christmas shopping and cold weather often occur together that Christmas shopping causes cold weather, which is a ridiculous notion but you wouldn't believe the amount of intelligent people make this mistake when it confirms a personal bias (myself included!).
I'm not saying that dairy doesn't cause issues for some, possibly a lot of people, it does. But if your a healthy person that has no leaky gut or auto-immune issues, then dairy can be a good source of nutrition, especially K2 if you don't eat organ meats. The best way to have it is raw and organic but failing that organic will do.