weakho
...no law requires that he be in business. What law requires that he not be in business?
IMHO, he has the right to refuse to train anyone he feels might use this training to commit crimes. Personally I wouldn't train muslims or democrats either. Neither would I train folks who belong to militia's or violent anti abortion nut jobs nor druggies nor alcoholics (non recovering) or people who believe in little green men from other planets. I woulda refused to train loughner based on his appearance alone.

Liberals are like a "Slinky". Totally useless, but somehow ya can't help but smile when you see one tumble down a flight of stairs!