The point of Reddit, and now Lemmy by extension, is a sort of link aggregator + comments. As with all content: sure, general sites all exist for that porn, but sometimes if you want more specific categories it’s a lot easier to have community collected content that is sorted.

If someone wishes to spin up an instance for it, so be it. You are welcome to ignore it and not federate with it. That’s the point of the fediverse.