As far as USA goes - countries dont have friends they have shared interests. They are allies because their interests largely align, but they are very far away from perfectly aligning. I think people believe the propaganda that Israel is a vassal of USA too much - that isn't the case; Israel has more than enough power to plot their own foreign policy and they dont hesitate to do so when it suits their interests, just like any other country does when they have the ability.
For several reasons. Israel will never try to win a popularity contest with moderately educated college kids that will change their opinion in a few years anyway. To do that would be entirely stupid.
For in the middle east such messages do serve a purpose. Main reason here is the election of course.