I expect and understand these kinds of questions when I cross borders. But when I am a US citizen traveling within the US, these type of questions certainly raise constitutional questions.

I mean, how would you feel explaining to a TSO that your reason for traveling was for reconstruction surgery following a mastectomy (and likely having to explain to the TSO what a mastectomy is because he is clueless)? What if your reason for traveling was for confidential meetings related to a possible M&A and an employee of a competitor was behind you in line? These aren't one-off situations. These are everyday occurrences.

None of us want a repeat of events from ten years ago. But what I do (legally) within the borders of my own country is nobody else's business.