A few points here.
The ai tags are meta information. They do not show up in the info box.
If you see a tag concerning ai in the info box, the developer used one of the 10 regular tags to tag it such. These tags are not meta information. Itch has freestyle tagging, so this is unfortunately possible adding to everyone's confusion. Also, because Itch implemented the filter for the ai information as pseudo tags, available with the regular tag filtering. It is as confusing as it sounds. The only way currently to check if a game has the ai tags is to browse with the ai tags and basically see, if it shows up or not. Also, ai tagging is mandatory only for assets. Read here https://itch.io/t/4309690/generative-ai-disclosure-tagging In my opinion the guidelines ask for a description of ai usage anyway. I am also of the opinion that it is unfair to lump code and assets together under the no-ai filter.
You can suggest tags to a developer in the comment section. But Itch has freestyle tagging. There is no tags that are mandatory. You can even have project without tags. What is mandatory is certain meta information. Like ai info for assets or if a project is nsfw or not.
Hiding tags is often wished for. There is an undocumented feature to filter out one tag. I never found a good use for that, as tags are unreliable. Imho it is better to search for what you seek. Just add this to your browse bookmark: "?exclude=tg.visual-novel" (without quotes, and exchange for the tag you want to filter. Only works if you are logged into your Itch account.)
And I believe a far more powerful for browsing is to mark games as already seen. I even made a tool for that ;-)