I'm a left handed person and I too play right (normal) handed. I personally fingerpick all my songs, I hardly (if ever) use a pick. But ofcourse everyones different. I think that I, along with most other left handians, start off playing with a right handed guitar because that's what's lying around the house. It's just easier and it was there, for myself, because my dad plays a bit of guitar. If a friend or someone has a guitar they would probably just learn it that way instead of buying a new guitar.

So for myself it was mainly a convinience thing, but now that I've been playing for almost 2 years now, I cannot play at all left handed and wouldn't want to even if I did own a guitar suited for that.