I loved the episode. Just like I don't take the PC babies as representing everyone who complains about injustice, I don't take the Buddha Box users as meant to represent all cases of people with anxiety. Obviously, not everyone in South Park is meant to have real anxiety issues, but people who have antisocial behavior connected to their technology stimulation addiction would happily use the Buddha Box as a way of validating their unhealthy behavior. I think it's a commentary on antisocial phone use, not a commentary on people with anxiety disorders.
Perhaps you're just being a PC baby