You're right, it does sound kind of Rambo, doesn't it? He's actually a very conservative and experienced guy, the best tech at our local dealer for 14 years before leaving to start up his own shop. I've seen him do it, very gingerly, just sort of gets it close to his face, probably does that since he's always wearing rubber gloves and maybe can't feel it with his hands as well.
I think his point is just that most folks (present company excepted) don't really warm up their transmission fluid adequately, thinking that if engine coolant > 80 degrees, then trans. fluid must be maximally warm, which it is NOT in most cases. This leads the unwary to overfill their transmission, if they use the upper mark, and we all know that ain't a good think for an automatic. . .