Regarding the original list, it's likely only 2 and 5 would pass muster as being issues that antitrust laws would actually be able to deal with effectively. Number 3? Might be an issue if you can frame the argument in a manner more consistent with antitrust concerns. 1 and 4 are probably just emotional frustration leading the poster to say, "These must be illegal because I don't like them."
We need to focus on real issues if we want to be taken seriously. Right now privacy and security activists just sound shrill and unconvincing. Part of that lack of credibility is the tendency to focus on things that are not true issues from a legal perspective as opposed to the slam dunk type issues that stare us in the face.
This is why these issues are so hard to build a consensus around in the larger population, because lawyers hear the complaints of some activists, and they just laugh. Then those lawyers go off and work on things that actually have a chance in Hell of working. So I applaud the move to have an antitrust investigation, but we shouldn't be under the impression that every little thing some guy doesn't like is part of it. There are very specific families of issues that are reviewed for propriety, and if action needs to be taken, it is.
Doesn't mean we should waste the time of these states looking into why some guy's youtube account was cancelled. That, and other ridiculously trivial issues like it, are not what this is about. So we shouldn't even set up those expectations. Particularly not in lieu of getting the word out to the larger society about real antitrust issues. (Of which Google and FB are the main offenders.)