The point of lemmy is:

“Despite the conservative talking point that big tech is dominated by “leftist propaganda”, it is liberal, and pro-US, not left (leftism referring to the broad category of anti-capitalism). Reddit has banned its share of leftist users and communities, and the Reddit admins via announcement posts repeatedly vilify the US’s primary foreign-policy enemies as having “bot campaigns”, and “manipulating Reddit”, yet the default Reddit communities (/r/news, /r/pics, etc), who share a small number of moderators, push a line consistent with US foreign-policy interests. – Nutomic and I originally made Lemmy to fill the role as a federated alternative to Reddit, but as it grows, it has the potential become a main source of news and discussion, existing outside of the US’s jurisdictional domain and control.”

They could theoretically do… a bunch of illegal things to take the server down. Though, I’m sure that if that happened, they couldn’t take down the lemmyverse even if they hired the FBI to do that.