Because there are a lot of rich Jewish people in the USA who "Lobby" the government (give em money (bribe them)).
The problem is, if the USA would totally stop helping Israel, they´d get slaughtered in a very barbaric manner.
One could argue that they shouldn´t be there in the first place, taking over Palastine using terrorist tactics & now giving the Palastinians gip for trying the same thing to get it back.
But the generation which is there, normal working families with children etc. Do they deserve to get slaughtered, heads cut off and all that sort of sick thing some wrathfull Muslims participate in, just for being born in the wrong place at a bad time?
Should the USA take more interest in itself, by doing things like pumping the money into alternative energy to bring the country into a new technological era, instead of invading places based on lies.
I don´t know to be honest, If I was a US citizen I´d rather have more dollars in my pocket due to less tax. And let things abroad take their natural course.