Lemmy is inherently democratic. If you don't like a muni, or an instance, you go to another one. Without centralization dictatorship is impossible.
That said, it's not democracy, either: It's a federation of interdependent polities, each with their own laws and administrators. Which is good, because it allows for rapid response to spam, inappropriate content, and verbal violence.
And if the admins or moderators overreach, well, back to the first paragraph: we've got open borders, go homestead your own community on another instance. You literally cannot be silenced here.