Bradley Burston explains:

As with parents who become more and more indulgent the more clueless they realize they actually are - and the more out of control their kids get - Washington and the world have allowed Israel and the Palestinians both to run off the rails in whatever direction they happen to see fit at the moment.

Why? For the same reason that bad parents spoil their children:

They're afraid of them.

For generations, both Israelis and Palestinians have been snowing their respective allies, who have been afraid, either electorally or physically, of being perceived as not loving them enough.