The animal_humanoid tag is consistently misused. For those not in the know, this tag used to be animal_ears, and is intended to refer to anime catgirls and such. Blacklisting the tag creates quite a few false positives whenever I check on it. Just by a quick search, you can see the issue pretty quickly.
The tag was aliased because people figured it was too unintuitive that it specifically referred only to humans with animal ears, rather than anthro animals or normal animals with animal ears. Well, apparently animal_humanoid isn't any more intuitive, which doesn't surprise me. Because, you know, all furries are technically animal_humanoids if you think about it.
It's an important tag, but I'm not sure the ratio of false positives is satisfactory. I don't think it's just one or two problem users either. Plenty of people are going to see the tag and come to the conclusion that it is meant to mean the same thing as "anthro," and I don't think that problem will go away no matter how much maintenance it gets.