white supremacist subreddits like /r/europe are pro-Israel, probably only because it conveniently resonates with their anti-immigrant and anti-muslim messages.

The pro-Israeli stance of a Europe that is as antisemitic as it always has been is no new thing - even the Nazis considered forcing Europe's Jewish population to emigrate to Palestine as a potential "Final Solution" to their precious "Jewish Question" (it was dropped as a "solution" because Palestine was in British hands at the time). Christian Zionism predates Jewish Zionism - and it was always firmly based in European antisemitism... ie, the (very antisemitic) idea that Jewish people are "other" and cannot belong in "western" society. People are quick to forget - the post-WW2 era was the only time in "western" civilization's history that overt and brutal antisemitism wasn't the order of the day. From a historical perspective, it might even be considered an aberration for "western" society - and, considering the resurgence of of overt far-right ideology in the Global North, it may be an aberration that is coming to an end.

It’s like saying the people that support Palestine do so because they’re anti-Israel.

You cannot be pro-Palestinian and not be anti-Israel - that's no different than saying you're pro-black people but accept the existence of the Apartheid-regime in South Africa. To compromise is to simply excuse the continued repression of the former under the guise of "respectabity politics" - the politically correct term for "appeasement," I'd say.

but the common people do it because of how close their values and culture are to their own.

What "values" and "culture" would that be? A belief in "western" superiority as catalyzed through genocidal settler-colonialism? White supremacism, perhaps?