That's a good way to recognize assholes. In my school there is a kid who shutter, he's really nice and a lot of people have the time to hear him when he talks. Two years ago one of his classmates tried to making fun of him for one or two day but then she stopped because he didn't give a damn since all the others treat him nicely. This year the kid that made fun of him turned out to be very childish and superficial. Apparently your method is valid: people who can't stand those who stutter are often irresponsible