Actually they gave away Britain's house with Britain's permission.No, just like any invader wouldn't be welcome, that's the point.
The UN established a Jewish state because they all felt bad about the Holocaust (that they did very little to stop).
That would be like if a poor family's house burned down in a riot, and my solution would be to give them YOUR house, because I feel really bad about it. You didn't have anything to do with the house burning down, and giving them your house is no skin off my nose.