Your question is in no way different than asking why Muscovy has a right to the various regions that make up Russia, or why the Han should rule over what we call China, why Turks should not be kicked out of Anatolia, Arabs out of the Maghreb, or why Canada should not be turned over to the various first nations who were here first. I could at least respect that kind of moral consistency. However, when the rules are defined so that only one country in particular falls under their purview, I have to wonder if there are any ulterior motives.
My arguments for or against the existence of Israel are irrelevant. If they'd asked my permission I'd have said no, but it exists, and any argument where it must cease to exist is in the worst possible faith. If you consider Israel to be the only colonialist country in the world, I think you're simply an antisemite looking for any fig leaf you can find.
You really like metaphors.