We can & should demand at least gateways & mirrors if not at least a single alternative. Considering they have funding, they can self-host to actually control a forum or chat room as well as a code mirror (even if just HTTP with no forge). Folks are also undervaluing how some users are banned from access to these US-based platforms under US sanctions.

The pro-FOSS stance would be to get your communications off of being exclusively proprietary platforms. Developer & early adopter freedom & privacy matters—but instead they are choosing Discord & Microsoft GitHub as their only platforms.