this is much more complicated than it seems. To a large extent, there's no meaningful difference between "a corporation using its power" and "a group of like-minded people getting together to amplify their voices"

Well, there's a big difference, because we grant special limited-liability status to corporations -- but the big tech platforms don't really benefit that much from limited-liability because the corporations have more wealth than their owners/officers anyway (and virtually all of the wealth of the owners/officers is in their ownership stake anyway)