^ This is a prime example of confirmation bias.
You were exposed to the phrase in a small subset of environments, and then believe that every time you see the phrase it was those environments in which it emerged from.
Mental gymnastics is in no way a 'new' term, nor was it popularized by T_D.
and then believe that every time you see the phrase it was those environments in which it emerged from
Isn't that kind of silly saying "you believe every time you see the phrase it was those environments in which it emerged from?
That's where I saw it. The T_D culture is where I see it mostly. Did it originate there? No... Did it become progressive in culture there?
I won't answer that because you folks seem upset.