Why would smart people care about denim vs. trousers?
Let competitors wear pajamas- it makes no difference.
More generally, appearances are important because they are clear signs of attention and care. Something worth our respect is worth dressing up for, and a collective dressing up reinforces the importance and elevation of a given event or moment over other events or moments of lesser import.
Attention and care for appearances, not for the job to be done.
One could interpret it that the sharp looks are there as a cover for ... less than stellar competence.
You cannot win with statements like that.