Ok now how many of you actually do that? Facebook is social media, yet 2.1 billion people communicate with messenger as part of their daily private messenger. 

If we don’t make privacy by default, then we find that people will use whatever is most convenient, even if it means giving away their privacy. 

What you said is all valid and these are ways to use it without compromising your privacy, but the average person does not and will not think about it until it too late.