From an anarchist perspective: there's a difference between vandalizing a Walmart and vandalizing an online forum. Anarchists clearly recognize that vandalism is destructive. And destruction absolutely can be a liberatory act, e.g. vandalizing a Walmart. But if we're trying to construct a liberatory community connected by social media ... clearly, vandalism of said community is counterproductive.

Moderation allows trusted members of the community to take action against people trying to wreck our communities. It is an act which asserts our freedom of association in any case, a corollary of which is our freedom to disassociate, and an act of community defense in extreme cases (e.g. yeeting Nazis to Hell). That is not to say that forum moderation, including Lemmy's and PieFed's implementations, is beyond critique or is incapable of reproducing existing hierarchies. But IMO, moderation can be a perfectly valid tool in an anarchist toolkit.