private equity, this is the price of admission. That's what the interviewer was telling him. Whether that guy has his priorities straight is irrelevant - a job interview is not the place to have this conversation. You let the guy know that you're new to this and willing to learn the ropes, and this is one of the things you'll have to figure out.
Assuming this guy's not trolling (a big assumption), the interviewee here did a huge disservice to the person who referred him for this job by making a bad impression with his dress (which was, I imagine, surmountable) and then compounding it by arguing with the guy about the importance of dress in the job (which isn't surmountable).