Actually there is quite a bit of merit in discussing the limits that are placed, or could/should be placed, on the mega-platforms in terms of what content they

Actually there is quite a bit of merit in discussing the limits that are placed, or could/should be placed, on the mega-platforms in terms of what content they are allowed to censor. This is not a definitively answered question, and is something that the courts are indeed struggling with. It is actually not as simple as having a ToS which says “we can deny service to anyone for any reason”. Twitter, for example, advertised itself as a neutral platform. Therefore it would be an unfair and deceptive business practice (per the FTC) for it to institute politically motivated account terminations. Similarly, Google certainly has the capability to influence both election turnout and perhaps even voting itself through the type of content it surfaces, and Congress has held many hearings and even heard testimony from Pichai on this exact topic.