Many people rightly say that Israel is the last of the [overt] Western colonial enterprises in the world.
However, Israel was not always as 'central' to the Western interests as it is now. The Brits resisted the formation of Israel to some extent despite the Balfour Declaration and the British soldiers were targeted and killed by the Zionists. The Americans were turning away Jewish refugees escaping Hitler. Anti-Semitism was widespread in Europe though Hitler/Germans are conveniently singled out. In the 1956 Suez Canal related war, Americans were not so much about helping Israel--on the contrary.
There have been many reasons and I believe in what John Mearsheimer said in 2006 in his 'The Israel Lobby' book: It is primarily the Israel Lobby in America now. John goes into great details about as to how Israel gained its primacy, especially after the 1967 War, through using its parasitic Lobby in America. It would be a long discussion if we go into that book. But what was concluded by him then and remains true: Israel no longer serves the American Strategic interests in the Middle East and on the contrary is now a liability to the American interests.
So, yes, a colonial enterprise for a long time but it is no longer the useful tool and is now, in fact, a liability. I tend to think there is paralysis in Washington when it comes to Israel. Officials are too resigned and are in some stagnation mode despite knowing the losing American interests in the Middle East. The consequences for any officials should they dare challenge Israel are almost always very harsh, so why bother? And history is going to judge Israel as the single most damaging entity which led to the expulsion of Americans from the MENA region, thus giving the advantage to China led block. It is already happening.