From their perspective, perhaps. From the perspective of passengers, some of these questions are not mundane, but are sensitive information (where are you staying, how long will you be gone, etc) and the implied threat is that if you don't answer our questions, something will happen to you. And there apparently have been retaliations for some folks who decline to answer the more intrusive questions. All this quite apart from the unfounded pseudo science behind it (the GAO said this in their report) and practiced by unqualified personnel to boot.

The spectacle of of US citizen being shaken down like this traveling their own country is a sad sight.