True, it makes it worse. Self-taught or not, he could fight and the Taiji guy could not. He at least has the mentality and willingness to punch somebody out. That alone would have given him the advantage over a complete non-fighter, MAist or not. Similar to the many incidences where black belts in various MA have been beaten by untrained street fighters.
Actually, there were some notable MMA fighters who (or so I've heard) at least claimed to have started out self-taught: Rich Franklin, Evan Tanner, Cro-Cop, etc. Of course, they didn't remain self-taught.