People can delete their messages but I haven't seen it happen enough that it really bothers me.

Yeah it's preferable for news stories to remain up forever. Maybe IPFS could eventually become popular enough that news organizations use it as well. But in the meantime archivists can use it to archive news stories permanently. I agree that it's important for news articles, scientific articles, statements from politicians etc. to not be memoryholed. But ideally, right wing groups should use private anonymous networks with auto-disappearing messages because it's safer. Members being targeted by law enforcement has a much worse effect on a group than any negatives that might come from people deleting their own messages.