You are absolutely correct, that having a permit to carry a concealed weapon does not rule out the possibility that one is a criminal. But, in my 20 years of police work, I have never arrested a person who also had a CCL. Traffic offenses yes, but no serious crimes.
We make a good faith effort to insure the people who take our classes are not criminals, that's all. Frankly, based on your attitude, I am glad you are not coming to our school. We don't need your type here.