Wait... WHAT!? That's SO much worse than shadow-banning, primarily because it is exactly shadow-banning, except it's not, except it is. Lemmy really needs to move faster to fix these FOUNDATIONAL cracks involving (checks notes) "making posts to communities". Is the issue at least fixed on the PieFed side?
The more time that passes, the more that I am laughing that lemmy.ml mods have been doing what OP claimed that the DO mods did since Lemmy started, but there nobody bats an eye no major instances seem to care, whereas here one person gets banned from a single instance and immediately out go the calls for full defederation of the entire instance, with most people calling him a PTB. Which might be the case, but the evidence presented is nowhere close to sufficient to demonstrate that, given rule #4 of that community.
Btw I (hope that I) never claimed that lemmy.ml did not have the right to ban people who were not a fit for their communities - only that doing so for hidden reasons that are never written down anywhere is what makes them authoritarian. Which here those mods seemed to have done, with their rule #4? (It also makes them authoritarian to have done so without telling people, and I strongly hope that PieFed is not making that mistake as well - not shadow banning people is basically the primary claim to fame for Lemmy, other than the hope for something better in the future, which as the years drag on and the software remains just as if not more authoritarian than Reddit, the latter waxes mighty thin these days.)