Tankie is a pejorative label generally applied to authoritarian communists, especially those who support acts of repression by such regimes or their allies. More specifically, the term has been applied to those who express support for one-party Marxist–Leninist socialist republics, whether contemporary or historical.
You mean a fork? Why not? A copyright assignment and relicensing dispute is what caused a LibreOffice to fork from OpenOffice. Forks is a great feature of FOSS and there are normal.
Best recent example I bumped into was OrcaSlicer it's a fork of a fork of a fork, merging in some of a fourth fork.
I think the lemmy software itself isn't so much the problem (in that it isn't politically moderated), but the way he moderated his own instances make a fairly compelling reason for defederation