You know, reading this, a thought just occurred to me: in the past, I've told many people how strange I find antisemitism. When I was a kid, the only thing that made the Jewish kids different was that they had Hannukah instead of Christmas, but otherwise, they seemed indistinguishable from other "white" kids to me.

Reading your breakdown here, though, made me realize something: growing up in the suburbs in the PMC, what I was noticing was that the kids and their families were the same class as me, which I contrasted with the more obvious ethnic differences (Korean, black, etc) some other kids in the same class had (not that those seemed important either, but I could at least kinda-sorta understand how folks might see it as a "real" difference).

So, from this point of view, your notion that folks who buy into racial/ethnic identities, but are actually subconsciously equating them with their class (such as, say, some wage class whites or rebellious PMC white kids who pick up the alt right for lulz/shock, or on the other hand, woke warriors who equate the welfare class with black folks) makes a lot of sense. If that's the what's happening, you can put together a theory: these folks see a problem between their ingroup and an outgroup (their differences with the PMC), they're pre-disposed to think that the differences that matter are racial differences, so they look at the PMC and ask "what race could this really be?" and they end up with "Jews", since most Jews in Western countries are pretty firmly part of the PMC these days.

Whether the above is right or not, interesting stuff to consider, at any rate!