I hope it's not taboo to ressurect an old thread here.
Serra's assertion that he "does not fight" is only kinda true. He doesn't fight MMA, but he is a world submission and grappling expert who has beaten a lot of tough opponents in BJJ and grappling tournaments.
You don't have to be a total MMA fighter to coach well, and from what I've seen on the show he coaches what he is best at, BJJ. I've never seen him try to teach standup striking, for instance.
In the context of dissing the Royce's MMA skills, he really should be more respectful since he doesn't fight MMA. But he is hardly some "average fan" like some people claim. He may be an asshole, but he is a grappling and submissions savant.