Personally I think "lemmings" is great because it feels slightly ironically funny and mildly self-deprecating but not in a bad way. Like, the stereotype of lemmings, even though it isn't really true, is that they're blind followers, which doesn't at all fit the fediverse given it's decentralized nature and lack of one singular direction. Meanwhile, calling some group of people lemmings feels slightly derogatory, but calling oneself something like that gives the feeling of not taking oneself too seriously.