So no identified reason why membership of the UN and UNESCO for Palestine would be against the interests of Israel, but voting for it counts as being "anti-Israel".

I don't know how oublic opinion breaks down over this in Israel - butr it's interesting to see that in the USA, it appears that it actually runs runs in favour of Palestinian statehood. What Keith might call "anti-Israel. From this Israeli source: "The US and the Philippines showed the highest rates of opposition to UN recognition with 36% each. However, 45% of those surveyed in the US and 56% of those in the Philippines cast their vote in favor."