So um here's the thing.
The fediverse is a network of interconnected servers/instances that are independently hosted.
Within the fediverse, there's Lemmy
There are many different "servers" (I'm just gonna call it servers, instances is not a commonly used word) of Lemmy. Each have different owners. But they all run the Lemmy software of their servers.
The Lemmy software is an open source project, contributed by many different people who know how to code. The main developers believe in Marxism-Leninism, basically what countries like USSR and People's Republic of China claim to also follow this ideology (or at least they used to).
lemmy.ml is one of the first servers, run by the main developers.
So there, if you disagree with their ideology, you should probably use a different server.