The Israelis don't buy that many weapons from America, either directly nor by having the American government buy and gift the weapons. It's significant, but weapon sales alone can't explain the fanaticism of American politicians in both parties and the American public. Weapon sales can't explain why states like Texas would pass laws requiring school teachers to swear oaths of loyalty to Israel. It can't explain why small town diners in rural America hang Israeli flags, or why America/Israel combined flag fridge magnets and patches are on sale at every truckstop.

The American public are absolutely fanatical about Israel and it's mostly because of their insane religious beliefs, not because they're all invested in the defense industry.

Look up figures for how much defense material Israel actually imports from America vs other countries. Have you ever heard of American politicians getting grilled at debates about how much they support Japan? Have you ever heard American politicians boasting that they support Qatar far more than their opponent? How many American politicians mention support for Australia during their campaign rallies? Support for Israel is a unique phenomenon in American politics, not merely a straight forward function of arms exports. It's because the American people have loyalty to Israel specifically, because their bibles say that Israel is important and say nothing about South Korea.