I think proper exclusion filters would be a great addition to Itch, and I'd go as far as suggesting a "Don't show me this again" button, as proposed in this thread. Youtube, for example, already has this kind of feature — you can block channels from being pushed to you by the algorithm, and you can indicate that you aren't interested in the kind of content a video provides. (FYI I wouldn't say Youtube is a shining example of how a platform should be managed, but that's one good feature.) This kind of feature just makes it easier to find whatever it is that you want and, well, Itch is a marketplace, delivering what you want is always in the interest of a marketplace!
Also, if it means anything, I'm one of the people working on the gay furry visual novels you mentioned. Now speaking as a developer and user, I'd be happy if this feature got implemented because I want to use it myself (I don't like horror games!) but mainly because we don't want our games to get thrown at people's faces either. We don't want to be a nuisance! I can't speak for everyone making LGBT/furry games but my team and I are fully aware that what we are developing isn't most people's thing, and there's absolutely nothing wrong with not wanting to see it recommended to you! So if this feature got implemented I could rest assured that we aren't getting on people's way. I think it'd make Itch an objectively better platform for everyone.