—”Why do Israelis seem to be more socially liberal than Americans?”—
Because Jewish civilization makes use of the female reproductive strategy at all levels, which is why Jewish civlization has always been leftist, all but invented modern leftism, has produced most of the leftist literature, and continues to championed leftism today.
The fact that this strategy lost them a homeland, and has had them prosecuted and exterminated round the world, except where the west tolerated them seems to be lost on them and the foolish people for whom leftist strategies (maximizing consumption, and parasitism upon the commons) are desirable.
Whether this is biological or cultural is something we haven’t established yet, but my money is on yes by a long shot from the data I have seen so far.
https://www.quora.com/Why-do-Israelis-seem-to-be-more-socially-liberal-than-Americans