To put it another way, when I first joined, it was to kbin.social. Kbin has a feature to help people discover new communities where it will suggest random comments. This leads to...rather dramatic cross-pollination. So, for example, I remember looking at a technology community on pawb.social. Some other random kbin.social user also showed up there, I'm sure via random comment, and was complaining that everyone in the forum was a furry. I mean...yeah, you just hopped right into the middle of their den. Same thing with yiffit.net and probably a number of other instances. Does that mean that the Threadiverse is all furries? Well, no. I'd say that it's disproportionately so compared to Reddit, but it's more that it's got special-interest instances.

Or transexual users on lemmy.blahaj.zone.

Or porn enthusiasts on lemmynsfw.com.

Or underage anime porn fans on burggit.moe.

Or science enthusiasts on mander.xyz.

Or Star Trek fans on startrek.website.

Hop onto any of those or communities on those, and you're likely to find a lot of content of the sort that the instance focuses on. But if your instance doesn't federate with them, you may not see that material at all, nor the users on those instances.