I do not think the circumstances are the same, John McAfee received payments from new projects to promote their coins and there are even some accusations that he dumped some coins after posting his tweets while Elon Musk is just posting some tweets regarding his holdings, while the difference may not seem to be that important I think it is, so Elon does not have anything to worry about, John McAfee on the other hand will have a difficult time proving his innocence.