Instead of a conspiracy or coordinated campaign against Elon Musk, what if a lot of people have come to think that he's a douchebag and upvote links about him saying/doing what they see as douchey things? Maybe he's actually done some stuff over the last few years that's made him genuinely unpopular with a lot of people; maybe it's not because "They" are trying to destroy him, but because many people actually find his behavior off-putting.