Correct, and that's exactly why it does not work for group things.

If fedi is like email, and it is similar in many ways, a Lemmy community is like a mailing list. People can send to the list and the threads on the list from different servers. And there can be separate communities about the same topics just as there can be separate mailing lists about the same topics.

But hashtags in email wouldn't work as a replacement for mailing lists. Hashtags in email can still have some use, within a mailing list or in a specific conversation, but it's something very different from a mailing list.

On kbin, if people think that "Oh, here is where the posts about cycling will show up" but the magazine is just based around a hashtag, there's no way for people to participate deliberately. It's misleading.

Using hashtags as if it were tumblr or twitter is anti-decentralization and drives people into using the biggest instances only. Groups a la gup.pe and Lemmy and Friendica is a solution to that. It's only a partially decentralized solution, since each group itself is centrally hosted (exactly like mailing lists were), but it's at least a solution, whereas misusing hashtags that way isn't.

@ada @meteorswarm