The important line that is being crossed here is that you can get banned from Twitter/Facebook/Google/whomever for saying something that is not illegal but is in the opinion of the company objectionable.
No utility has the power to disconnect me if I do something they think is objectionable with their service. And that goes to the heart of what people seem to want from "regulating as a utility" (a phrase that is terrifying in its vagueness) - they want freedom to voice unpopular opinions and let those who agree, agree.