The problem has been mention earlier in https://wallhaven.cc/forums/thread/4309, and not well addressed till this day (probably just the tag "men" was fixed by removing an alias).
The items in Tag Blacklist seem to try to match by ALL tag content, including aliases, even partly. For example, if I add "CGI" to my blacklist, images having "ass" also get hidden - my guess is, because "CGI" has "CGI ass" among its aliases.
The worst thing with this behavior is that it is UNEXPECTED. There are plenty of tags that have lots of aliases, some of which are rather weird. And I want to block only the content that I want blocked! I'm totally okay with asses, if you know what I mean. =)
So my suggestion is to match excluded tags exactly by the tag name. I don't see any cases where switching from the current mechanism would worsen user experience.

