If the definition of what it is to be American is warped, specifically, that it takes more than citizenship to be welcomed home, then that should come into the discussion of these cases of mistreated foreigners.
Race is always complex, especially because racism illegal. It becomes a subtle and hard to describe thing. Maybe "random search" is a good way to describe it.
Ultimately, it makes me feel like I'm being delusional. I hope I am.
That story is about the TSA and local police, not the CBP. Very different.
Also, a US Citizen returning to the US does not have to answer any questions (apart from the written customs declaration) and cannot be denied re-entry to the US. (Although, as always, agents may abuse people.)