The only people that believe Israel was given to Jews by God are Jews and Christians. So, hopefully, you could understand (that's all I'm asking for is understanding) why Arabs, particularly Palestinians, are upset.

This is exactly why religion and politics, of any nature, don't mix. The realm of politics has to be big enough for everyone to have a voice. But not everyone believes the same thing religiously. It's hard to make a political compromise, which is absolutely necessary, especially in this case, when both sides think God is with them.