On sight, people automatically and subconsciously profile you according to your appearance and what you are wearing, etc. and assign you to the closest stereotype they have in their mind of you, and then respond to you and expect you to act congruent with that stereotype. They do not treat you like a special snowflake blank slate and attempt to create a highly accurate personality profile of you based on all of your behaviors, they simply do not have the time or desire to. A heuristic cognitive approach is much more time and energy efficient and in most cases just as accurate.
As you all should know by now, PUA is all about faking having high status by supposedly emulating the behavior of someone who is high status. Why it doesnt work is because status is not primarily determined through examining someones behavior, its determined through watching how other people act around the person. And when you have no status, when you arent popular, but youre pretending to be, people quickly see through the charade by the fact that people around you dont treat you as a high status person.