Lots of major free software projects are hosted by the project creators to avoid being screwed over by proprietary services.
Examples
If Microsoft were to release a competing link aggregator; then they could persuade GitHub (Microsoft’s subsidiary) into locking or removing the main repository for Lemmy’s source code.
I entirely agree, but there’s currently limitations with selfhosted forges. It’s hard to ask everyone who wants to report a bug or submit a patch to create yet another account on yet another forge. in that sense, mailing list driven development is very good.
i personally would suggest to wait until gitea supports federation: as soon as it becomes possible to receive contributions from well-moderated forges like codeberg.org tildegit.org forge.chapril.org (or even gitlab instances like 0xacab.org if forgefriends project is successful) then it will be very interesting for a broad project like lemmy to have its own forge. in the meantime, we’re stuck in this status quo where we all need a github account and i think in the specific case of lemmy it’s a fair trade off