no, i think he is just pointing out the unfair, illogical stance.. the allow formal and informal, and (formal and) casual, but not (casual and) uncasual..

formal and informal is not the same as casual..

I might formally adress someone as Dr Smith, in a public setting, but in private i would be informal, and call them Joan. but i might also be casual, and call someone Dr. Joan, (or as we do here, Dr bill!) uncasual is a bit harder, but i see it as valid word. (scrabble dictionary not withstanding!)