That's a good point. I find Zulip better than Slack/Discord for discourse (even better than mailing lists, with some caveats, and it's Apache-licensed:
I knew about Zulip but wasn’t aware of the free hosted plan. I can truly see it now as an alternative for orgs who can’t afford running these things themselves.
It doesn't directly, only as a meme, or archetype. The same way that beer is not directly related to the concept of gratis, but you still use it in the illustrative phrase "free as in beer".
https://zulipchat.com/