Well I do think you have some obligation to defend them, at least to yourself. But I agree you have the right to mind your own business and believe what you will, and most wouldn't disagree with that. Others also have a right to question your beliefs and ask for justifications and reasons. And posting to a public discussion thread invites it.
I think describing faith as the following of a moral and social teaching is interesting, and an important thing to understand. When using the word faith to an atheist at least, the image of belief without evidence is what is conjured. Using the term to describe a system of morals and social standards starts a whole different conversation.
I subscribe to a lot of what Jesus taught personally as well. I also discard a lot of what was taught in the Bible because it is either outdated or socially bound.
As to Paul, it's true that we don't know.. and we will never really know because of the lack of reliable sources of information. His transformation may have been much more gradual. Things have a way of changing and being romanticized after retelling, even by the person who experienced them
