Your self restraint was very admirable. It's obvious it was out of love for your son that you were able to control your impulses. The first thought that came into my mind was snatching my son up and announcing that he would never belong to a cult as I marched out the door. The nerve!
You'll find a way to help your son understand your decision to never darken the KH doorway again. Afterall, you truly love him and don't view him as a possession or conquest as they do.