Because it was...

The Allies didn't fight WW2 to save the Jewish people.

Only half of the Holocaust victims were because they were Jewish, WW2 was about Germany invading everyone.

So after the war, the reason for creating Israel wasn't some kind of reparation, it was because even the Allies were incredibly bigoted and still didn't want Jewish populations in their countries. So England picked some occupied land they controlled in the Middle East, kicked out the inhabitants and "gave" it to a religion. Which has literally never resulted in peace in all of human history.

They 100% knew this would create more problems. But it ensured those problems would happen far away from Europe.

If you want to understand why Europe didn't like Jewish populations, it's because for centuries Christianity didn't allow charging another Christian interest.

Rich Christians stopped loaning money since they couldn't make money from it. And Jewish citizens filled that role. Even after Christianity got rid of that rule, Jewish lenders were already established.

The hatred people had with Jewish citizens, was really just hatred of capitalism. It's just the only time they interacted with Jewish people was taking out loans and other financial stuff.

It's just most people only know the incredibly simplified fairy tale version they learned in history class decades ago.