That's just wrong. Totally ahistorical.
There's a good chunk of the rest of the fediverse that's more right leaning, for the most part they've actively avoided Lemmy because Lemmy was actively hostile to any kind of wrongthink. It was one of the things that really limited it's growth because you could only be on Lemmy if you believed exactly what you were told to believe.
I stayed on the threadiverse through lotide despite it all, and despite having some pretty limited takes, I quickly found myself banned or defederated from many instances. To this day I don't participate on those instances because I'm not welcome. Wolfballs and exploding-heads came to exist, but were similarly rejected and even now the very first thing to be done by many instances is defederating from those instances.
I've heard through the grapevine that some of the people who run fediverse instances are considering starting Lemmy instances now that the platform is growing.