The requirement to ask the basic security questions which we are always asked and which we respond to automatically (did you pack your bags yourself, etc) are mandated for all carriers, that is correct. The requirement to check documentation for validity is also mandated (although not a security issue but an immigration one - and air carriers are fined if they carry passengers without valid documentation). However, "profiling" and asking you who you work for, where you work, and who you slept with last night are not mandated and are, in most cases, not carried out by non-US flag carriers, and that is the big difference.

I don't think anyone here is complaining about "the 3 questions", but about the interrogation that is carried out by US flag carriers which often delves deep into what one might call one's personal sphere. I certainly have never been subject to such questioning when flying on a non-US flag carrier.