I believe most of the motivation to debate others comes not from some altruistic desire to 'enlighten' them
That was my desire. The claims looked impressive, and too many to be a coincidence, now I know how they are done I wanted everyone else to know too. But it's important that my arguments must be based on provable facts, otherwise I am in no better a position than the altruistic gestures of those who want me to go to heaven.
but to convince oneself one is 'right' and to make oneself feel more secure.
I think that is the case for religion certainly, because the only credibility in the incredible claim for God is the fact that so many other people say it is credible. My position on the other hand is based on a combination of evidence (proving what I believe) and lack of evidence (preventing me from believing what I do not believe.) I don't need others to agree with my current opinion, when I was deluded I DID need that.
Personally I passed that stage long ago. I have nothing to 'prove' to myself.
Ironically that makes me more accepting of opposing opinions.
I can understand why people have these opinions, but it does frustrate me that many won't be open minded. I on the other hand will remain open minded, if someone shows me evidence of something supernatural I will accept it.