You have named the deeper problem precisly. Tags are inaccurate. For tag filtering you need precise tags in the first place. So my theory why this is not implemented yet, is, that it would be not very helpful, because the tags you could filter, are not helpful in the first place. Little gain for much work. Low priority.
That userscript fetches the tags and blurs the list while doing so, I assume. The comment about ddos implies that it fetches all of them in short succcession. So basically all the displayed items will get their tags fetched and get hidden accordingly.
Will this trigger the interaction for scoring the recommendations? Because, it would trigger all the stuff that is on top of the lists, like all those horrible games people complain about . That would tell itch you like to interact with them and recommend them to you in the future, if it will get triggered.
