What are Joe Rogan's MMA expert credentials?

Why does distinction need to be made? It's just an excuse for him to bash on kung-fu, TKD and karate to comparatively aggrandize the disciplines that are actually contributing factors in modern MMA (which, lo and behold, he has a direct financial interest in hyping). Pure salesman sleaze. Cheap shots. Every discipline has charlatans practicing it, that goes without saying. There are probably rip-off BJJ schools popping up in most major cities now, just as soccer moms have been dropping the kids off at "karate classes" that are total BS for generations. There are tons of incompetent crooks running boxing gyms out in the suburbs where people don't know any better. Wrestling is probably the safest and most "pure" of all, mainly because it's been institutionalized in the academic system so that there is uniformity in standards. In just about everything else, you have to dig through a haystack to find a good, honest needle. It's a byproduct of the average rube being completely ignorant about combat techniques - a little smoke and mirrors and you can sell them anything.

I just feel writing off what he seems to narrowly define as "TMA" en masse is foolish - he can't possibly know enough about them all. Especially considering kung fu itself is a very broad term applied to multitudes of different regional fighting arts.