Apologies, to clarify:

"These kinds of snap judgements I find very problematic. As if anyone... can make that kind of an assessment from a (highly contrived and stressful) 45-minute or so interaction with someone."

"snap judgement" in my reading, implies a rashness, lack of carelessness, or impulsiveness, (or arrogance, which is implied by OP)

My counter is that although it is not a lot of evidence, it is generally a very deliberate act.