Yes, it works poorly everywhere on the fediverse, is exactly what I'm saying.
Hashtags on Fedi can be good for organizing stuff within a single account or instance, or it can be used for other things like trigger specific bots, but they can not (as you know) work like an IRC channel like they did on Twitter.
That's why I'm not happy about kbin elevating that misfeature and legitimizing its misuse as if it were as robust as the other federated group protocols are. It's not the end of the world or the worst feature on the planet, I'm not that worked up about it, it's just not good, is all.
(Again, not blaming you for that ofc, you only reported on it, and that was awesome, thanks.)