if you are getting “punched down” (aka offended) by a joke posted on lemmy, by a random guy, you should realize that it is simply not that deep

I think you’ve misunderstood what punching down means. It has nothing to do with being offended. It’s about the relationship between the person telling the joke and the subject of the joke. For example, it’s generally fine for anyone to make jokes mocking rich people; but its not ok to make jokes mocking poor people unless you yourself are very obviously a poor person.