I'm glad more people are addressing this because it is a serious issue, arguably as bad as the bot epidemic.
But here it is in the Terms of Service. It's been there long before this shit started happening.
Intentionally tagging incorrect tags is abusing the tag system and therefore against the TOS. The posts that tag shit like images of cigarettes as celebrity names.
That's what the TOS is trying to avoid. Within good reason. OP is right; the longer this is condoned, the more people will join in, the more prevalent this gets, and the less relevant tags will become. Tags will be as relevant here as they are on Instagram or TikTok and shit.
That and it's just fucking annoying and disrespectful to other people's time, all for the sake of scrambling for popularity online whatsoever, let alone Tumblr out of all sites.
So to anyone still bitching on how this "unfair" because you want an excuse to abuse the algorithm to get likes on your dusty ass selfie, please fuck off back to one of those platforms instead.