And the folks who don't believe in angels, aren't they sort of proselytizing too?
I don't think so, Carol. My understanding of "proselytizing" is trying to convert someone else to one's religious beliefs. Saying you do not share those beliefs to someone who is proclaiming them to be the truth is not proselytizing, it's just expressing skepticism.
Otherwise, someone could say the tooth fairy really exists, and if you say, "No, she doesn't," you are proselytizing.