Pittsburgh and to a lesser degree Philadelphia have small but influential Jewish populations. The rest of PA is basically a Northern version of Kentucky but as long as Pittsburg and Philly are pro-Israel so will any politician coming out of there.
Not even specifically about this issue, but just because he's being a lapdog for the Trump admin after running as a Democrat. He keeps voting for Trump things.
This is a reasonable take. I don't think Trump's proposal would work, and I don't think he will proceed with that. But the question is what is what is a feasible proposal that would work for everyone? I don't think anyone has come up with anything feasible at this point.