This system could work is if the people who manage anime communities also enforced tagging borderline hentai with the hentai tag, which hopefully most wouldn’t take issue with. You could always still block the community/instance if they don’t follow this system.

Personally I’m not interested in hentai or anime, which is why a general anime filter encompassing both of these themes would be perfect for me.

Alternatively a filter for “hentai” and a more general “anime” filter would also be nice.