I'm no fan of US aid to Israel, but I do take Israel's side of the argument. If things were the way they should be, concerning funding to other countries, I'd probably donate a few bucks to Israel myself. Same goes for every other country on the planet. If Iran is making serious legitimate threats towards Israel, they should do everything they can to stop it.
As far as Iran threatening the US with a nuclear strike........ pffft, whatever. They might be nuts, but they're not suicidal. They know they would cease to exist if they made the move. Thats why they never will.