If I consciously decide to accept or reject a teaching of faith, why do some people call me "deceived"?

In discussion with a Baptist, I was called "deceived" because I attended my young cousin's baptism (he is now 2). He gave me the usual spiel about how evil Catholicism is (and I don't much care for his faith either), but I fail to see how I've been "deceived". Deceived by whom? What an odd choice of words. It's not like I'm some mindless puppet who has been dragged off and brainwashed. I choose my church because I believe what it teaches (for the most part).