Here are some mod logs from lemmy.ml (which is an instance run by the Lemmy devs) from a few years ago: https://raddle.me/f/TankiesGonnaTank/89852/the-lemmy-ml-admin-is-banning-anyone-that-mentions-stalin-or
Here's one of the Lemmy devs (you can tell it's them from their profile activity) denying genocide: https://old.reddit.com/r/MapPorn/comments/xq49ct/deleted_by_user/iq954mu/
Insisting that fascists are good, actually not fascists at all, as long as their nationalism makes them oppose the US (because the enemy of my enemy is a totally good guy!): https://old.reddit.com/r/DebateCommunism/comments/vgg2x3/thoughts_on_slavoj_zizek/id2cxb8/
There's more here: https://raddle.me/f/lobby/159606/-/comment/294792
But are you suggesting this somehow impacts Lemmy? It's an open backbone that anybody can use to create an instance - in fact, by default each modlog is open, could you do the same and link the moderator actions /u/spez took in 2018? Could you create your own Reddit and defederate half of the content if you wanted to?
As I see it, Lemmy's creators made their own instance to share their political views - that's it, of course they control the rules over there. They also made their technology public so that I can type out this comment on Lemmy.world, which follows a completely different set of rules.
all they had to say is "no we aren't tankies" and people just took them at their word lol
IMO it's a little more cynical than that, they rephrased the narrative into one that they could cleanly refuse and be quoted on. As others have pointed out, it is almost a certainty that 1) they do not consider themselves or their ideology to be fascist, and 2) they aren't supporting genocide if they do not acknowledge that the peoples in question are actually subject to genocide.