im just shooting that down outright, what about the devs or the server they run matters?

It matterd because the servers those devs run with their heavy pro authoritarian red fascist moderation and cultural bias were the two largest instances, the flagships, both by virtue of their size and their official nature. That size means they influence users' overall experience of the lemmy network's culture and atmosphere via posts and comments and votes, so yeah, you can sign up for a different instance and that local community won't have that atmosphere and those moderation problems but you're still connected in the network to the tankies and the tankies have the largest and most dominant instances so they have the most effect on the content of the network, and you can't completely avoid them except by deferating and basically hamstringing yourself by separating from the two largest instances.

Thanks to Beehaw and especially lemmy.world though, I think this is rapidly changing and won't be a significant problem for much longer, although there is the remaining concern that the developers' biases will show through in how they develop the underlying lemmy server software. For instance, unlike Mastodon, right now there is no way for you as an individual to block an entire instance, and I foresee it possibly being difficult to convince the lemmy developers to allow that, since one of the hallmarks of Marxist-Leninist ideology is a focus on mass movement building where everyone is forced to interact and join this one giant movement, even with people they don't like or can't get a long with, which could make them hostile to allowing more freedom of association in the fediverse. I'm already seeing tankies from lemmygrad accusing instances that defederate from them of sectarianism and endangering the "movement", in fact.