I used to have a friend that enjoyed audio as much as I did. The problem with him was that he didn't want to spend any more than what he thought he should pay.
He was always jealous and could hear the difference but over time he rationalized his point of view to the extent that he would intentionally get into arguments with salon owners, confronting them on the cost.
He would listen to any new piece of gear I bought and just stand there, getting upset and trying his best not to show it, but his facial expressions and body language betrayed his feelings. Jealousy. Pure and simple.
He could hear the differences but outright dismissed them as not important enough to justify the cost. His only joy was to play it as loud as he could and grin and smirk about it, as if he achieved something.
That is what I hear when people deride and decry such things as the efficacy of aftermarket power cords, or anything, for that matter. The put on a show, portraying themselves as out to save you from yourself.
All the best,
Nonoise