no, we really don't. Not every tool needs to be equipped for private discussions. ActivityPub and OStatus are used for Twitter-style communication. Those aren't high security communication services.
If my personal twitter-style communication got out it would be worse to me than my more private messages, but it is worse to me personally if all the twitter style communication gets out than only my more private messages.
You have to account for manipulative big data risks in your analysis, thinking only about your personal data is an outdated approach.
Doing it the other way around? We literally have 50 years of experience of that being a terrible, terrible idea.