One of the markers of a free society is the extent its citizens can travel freely. One day you decide to visit country X because you've heard they do an excellent cheese toastie. Fine. Go and taste the fine cheese toastie, the like of which has never been tasted on these shores.
Some countries, often those labelled as dictatorships or tyrannies, put restrictions on where their citizens can travel. For example Saudi Arabia prevents its citizens visiting Israel. Now, Israel is investigating three journalists, Lisa Goldman, Ron Ben Yishai and Tzur Sheizaf, on suspicion "of unauthorized travel to enemy states Syria and Lebanon to report for some of the country's main media outlets."
Sure Syrian and Lebanon are not exactly friendly towards Israel, and you may call them "enemy states", but in a free society citizens should be allowed freedom of movement inside and outside the country.
Every restriction on free movement of people makes a society less open and less free.