Den Defenders interview questions

Applied and received an interview within a week. I met with the HR rep. The question were simple and easy. Unfortunately the HR person didn’t let me interview with the actual sales manager. Why have an HR be the gatekeeper to a sales position when I am overqualified for the position? I have over 5 years of successful selling in a military role. Also the commission is only 5%! WHAT? The average sale is $4k but reps make 5%? Well, after taxes and vehicle upkeep. More like 3%.