My 2 cents as a long time internet user. The Browse feature currently lists 700k games. Some kind of sorting assistance is needed. It is just too much to find stuff. It is different from, let's say an adult video site *chough, cough*, where you engage in content for a few minutes. There, the thumbnails and previews are actually basically the content.
Here, a screenshot or even tags say practically nothing about a game. Well, ok, if you see boobies, it is Adult content, and if you see creepy stuff, it probably is horror, but even if the dev claims it is a Visual Novel, it could actually be a ressource management game made in a vn engine. Or a kinetic novel, what is only technically a VN.
Older games are not even tagged properly or at all. Not that the tagging of newer releases is accurate a lot.
While exlude feature would be nice, it is not practical. I saw this once on an adult site, but they had like a dozen tags and no more. You could then activate with a checkbox what you wanted (or not). itch has a 14 page listing of available tags...
Also, ... if Steam has an exlcude feature, I did not find it yet. While of course itch is not Steam, and a lot of stuff should not be copied, just because the big fish does or does not do it, it just shows there might be reasons for such a feature to not be implemented.
I think the reason is accuracy of tags. You would need a well defined and exhaustive list of tags, and that list cannot be too lare for intuitive usage, like say 20, better 10 items. But with hundreds of ill defined/applied tags ... exluding by tag is not gonna help you much, so why bother.
For the exclusion of sexual preferences, a straight-only tag would be the way to go. Positive searches are better than negative filters.
Regardless, for all this, the games need to have searchable attributes in the first place. And to copy from Steam and the Big Adult sites, there do be the concept of user suggested tags. As in, the users tag the content. While it might not be accurate everytime, it sure beats dev only tags that are incomplete, misleading (intentional or not) or right out missing from the start.
I am relativly new to itch, and what I missed so far the most were public reviews. I can imagine any number of good reasons to not have them, but user tagging would certainly be nice. In the More Information page those could be separated from the other tags, so that users know that they are from other users. And since people love nothing more than to correct others on the internet, if the tags would not match the game, the nitpickers would love to take action.