They can certainly decide for themselves. Regardless of whether their choices result in a loss of U.S. support, they will be the ones to make their own choices. And they will not be especially concerned whether 90% of the world is upset, if they feel that their national security requires it.
As for the 9/11 equivalence, proportionally the attacks on Israel were much, much worse. It’s a much smaller country, so while “only” about 1.2K Israelis were killed during 10/7 compared to the 3K killed on 9/11, Israel’s population is an order of magnitude smaller. Which means that a much larger proportion of the population has a direct connection to someone who was killed, or someone who is the parent or child of someone who was killed - far fewer “degrees of separation” from the victims. To say nothing of the fact that Israel was attacked from right next door, not from halfway around the world.
That’s why it’s so fanciful to believe that our opinions on what Israel should do are going to have much bearing on their response. The trauma of the Israeli electorate is going to drive that - not what the rest of the world thinks.