He isn't criticising a discipline. Wrestling is a skill, and one he's used occasionally in his fights. He's criticising the mindset that certain fighters have. Ones who game the system, relying on the existence of time limits and decisions to get their wins. Khabib will never be respected as a true fighter by true fight fans for this reason. It's the same reason Mike Tyson is so respected within boxing. He goes all out to finish his opponent legitimately. And as a result, is the most feared HW in boxing history, despite not being the best.