Why the Palestinians are reated horribly by Arabs

I think I have a handle on why everyone treats the Palestinians like crap in the Arab world. Apparently the problem with the Palestinians is Israel's fault. The worse they are treated the worse Israel looks, and it is more of a sign that Israel is the bad guy. From Lebanon's perspective, they hate them anyway (they were the main cause of the civil war here), and of course have no desire to make them more comfortable.