Thinking further on this, I think one aspect of the generational divide on I/P is that at least in the US, people my age and younger were taught a much more accurate version of US history in school than previous generations got. We've had to wrestle with that in a way that older people didn't.
It's obviously primarily a proxy for guilt (or sublimation thereof) from existing in a successful settler-colonial state by Americans who don't have any particular personal connection to Israel, on both sides.