I get the "it should not exist" part and I even get the "fuck Israel" bit mainly because you keep saying that. Well, Fuck AIDS, Fuck poverty, Fuck war, Fuck death and while we are at it Fuck greed, Fuck organised crime, Fuck unorganised crime, Fuck child abuse, Fuck inequality and you know what, fuck a lot of things.
This seems to be the new way of saying "I don't like this". Where "Fuck..."= "I don't like..." When looking at Israel's existence you could say "Fuck the reason of: the holocaust, Fuck the reason of: Europe, Fuck all the shit that happened to the Jews who live in Israel (I know YOU"RE NOT an antisemite but just cutting to the crunch, there is a shitload of Jews over in that there Isr-ay-el)". You could say all that couldn't you.
I believe Israel's existence was catalysed by what happened in WW2. I would be horrified to think that so many died just for a plot of land (but let's just go with that that theme because you don't really like zionists anyway and most Holocaust survivors/victims were...zionists, but don't worry, it's not Jews you hate, just the zionist ones.)
But as I said, you might not like this reason, you might not like another reason, hell, you might not like any reason but just like when I say Fuck offensive people, in reality the things I do not like still are there and are still existentially true no matter what I say about them.