I think most of the pro-Israel crowd legitimately believe that Israel's interests are aligned with the U.S.'s interests. The same with Canada, the U.K., and Australia. We share a set of values.

Israel does a lot of dirty work in fighting back against the darker forces of middle east terrorism, and it's reasonable to believe it is in the U.S.'s interest to let Israel do that work rather than take it on itself. It is a similar argument to why the U.S. should back Ukraine in the fight against Russia.

You can of course disagree with the above (arguing against interventionism; the risk of blowback; that Israel is creating more terrorism than it is solving; etc.), but I truly don't believe that any of the pro-Israel crowd believes they are acting against the U.S. interest.