Those are just nihilist. Actual anarchist generally aren’t the fuck shit up kind. Those are generally angsty young teens with very little understanding.
You are however 100% right about lemmy.ml. hexbear and Lemmygrad. They are all Marxist leninist. Which was an ill-conceived transitory authoritarian style anti communist government that was supposed to facilitate the build up to and transition to communism. But not communist itself. Which has failed everywhere it’s ever been tried. Much like capitalism if you go by it’s stated goals and ideals.
They love to blather on and on and on about communism and how great and wonderful it would be. And it would be. But everything they do is actually in opposition to it so they are very much fake/ performatory communists.