True, Belgium has borders that were determined by wars but also by the Germans, the British and the French by the Vienna Congress in 1815 in order to have a buffer state where they could wage their battles.

Israel's creation was approved by the UN (the first state, probably, after the UN was created itself); because of the UN's function (coordinating various conflicting powers), it issued resolutions asked for by either only arab nations, or almost the whole world, resolutions that were vetoed all the time, but were an indication (to Israel) about the shifting support by this or that country.
When I went to Israel in 1979 (maybe I'm the only regular one, here, who's actually been there), there were plenty of UN soldiers in Israel. But they were not actively involved in Israel itself, they were dealing with Lebanon. The UN soldiers were certainly not chastized by the Israeli population, quite the contrary.

Raoul