Or – get this – maybe they do it simply because they enjoy doing so, upvotes or no upvotes involved. Mistress Fortune, easily one of the oldest veteran members on this site, has posted literal hundreds of NSFW images and way less than half of them have anything over 5 upvotes (most of them have downvotes, in fact, so by your logic, she enjoys having her ego "attacked"), yet she does it regardless out of pure enjoyment of sharing with whom may be interested. She is not the only one either, just the one I believe exemplifies this case the best. Oh, and this has not stopped her from participating/contributing to the site's actual meme/subculture sides at leisure either. I doubt it does for anyone, honestly.

Just maybe, not everyone can be reduced to a negative stereotype backed up by nothing to prove it being a thing that actually exists just because you personally dislike the thing in question.

Post lewds on KYM and memes on PornHub. That seems to be the working meta right now.