You may not like this, but what it boils down to (as you indicated) is that unless you can improve the average American through education or cultural shift, you've got this pretty grim baseline. The PR culture is a response to that reality.
Does that mean that being honest is necessarily always the best thing to do? I'm not sure. It's worth considering. But I suspect that it will take a while for that kind of understanding to make headway in the higher levels of government.
(This goes with the caveat that people and organizations who simply lie all the time can get away with it. Basically, you either have to live firmly in reality, or you have to sell a version of the real world that's been thoroughly modified in order to conform to some vision. Living mostly in reality while occasionally lying is becoming an untenable strategy.)
Now, it's perhaps inevitable that they would use that lens, but it seems like it's the only lens they use.
Perhaps they're even right -- perhaps the average US citizen really is selfish and lacking in independent critical thinking skills, and perhaps we can't be trusted with the truth. But it means that anyone who knows better is constantly trying to read between the lines.
I blame the pervasive PR culture in the US, as well as basic stuff like a shit education system.