You have to be channel selective. There are popular channels I stopped following because of the propaganda issue for example. There are whole lemmy nodes that my node does not federate with for various reasons. The fediverse is a diverse shit show as a whole but one can choose to not follow crap or federate with nodes that allow crap. People can publish what they want but I do not have to listen to it. Nodes can moderate but if people do not like it, they can move to a node that better suits them. This diversity of content plus ability to filter the crap is a the huge power of Lemmy.