Let me paint you a picture of the fucked up situation in the Middle East.

If the US withdraws support of Israel, Iran attacks, they have pretty much openly stated that they would if that were to happen. If Iran attacks and Israel is out of options, Israel uses nukes. If Israel uses nukes, Pakistan uses nukes. Then India. During all of this, due to the massive amount of destabilization, extremist warlords start popping up. Russia and China start sticking their fingers into things, and not just in the Middle East, but any country/territory they've had their eye on, such as Taiwan. All of this takes place a stones throw away from European countries in NATO, and if any of them get hit, all of NATO is obligated to respond. That's not getting into the shit places like Turkey or North Korea would start during the chaos.

It's not as fucking simple as just cutting off Israel. It's a big, complicated, shitty machine that is likely to fucking explode if you remove the wrong pieces. And as shitty as it sounds, 40k casualties over 10 months is a lot less than the millions that would die within a week were shit to hit the fan.