I had a similar reaction a few years ago when I was talking with a co-worker who was a Jehovah's witness, and learned from her that as a rule they do not participate in elections, i.e. they don't vote. I was quietly outraged and made free with my opinion, but after a little contemplation and some internet research, I looked her up and apologized, and lucky for me, she had not been offended (or at least was kind enough to tell me she had not been offended).