Christian ones of course, although I've seen some good Muslim ones, though a lot that I just don't understand. Jewish memes kind of suck honestly from what I've seen, although it's likely that you appreciate them a lot more if you're Jewish and are more familiar with what they're about.
Personal familiarity with Judaism and Jewish culture is definitely more important to understanding Jewish memes than it was to understanding previous generations of Jewish humor. In addition to the high level of background knowledge necessary to understand most newer memes in general, a lot of very-online younger Jewish people are a bit more proprietary and insular about their religion and culture than most American Jews have been historically.
Just change "Leftist" to "Jewish" I guess?
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