We knew this from Echelon in the 1980s.
But the fact that people with access to your infrastructure also had access to your data was more or less well known ever since "the beginning", and it's also why internetworks other than the Internet were a thing for a long time.
> And yet, as a whole, we de facto continue to trust in opaque entities that provide valuable yet likely compromised services because it is convenient.
Don't forget the scarcity of alternatives though. It takes a lot of money to come up with a credible alternative to Juniper and Cisco. Siphoning personal data is what sells nowadays, not protecting it.
Phrases like If you want something to stay private, don't post it. are bandied about by the general public. Not just by single issue privacy advocates, but by people of all sorts.
1. https://en.wikipedia.org/wiki/Olmstead_v._United_States 2. http://scarinciattorney.com/olmstead-v-united-states-and-the...
The problem goes much deeper. It could be any "larger" corporation or government or other entity having enough manpower. It could even be parts of a corporation or government entity.
However which way you put it, a program of which you don't have access to the source cannot be trusted.