I don't see why you necessarily need some sort of logical origin or arbiter for morals to come from in order to act morally.

I don't like justifying intuition as an evolution thing.

We have intuition and it's a nice thing to have. We use it and it seems to work. Sasaki if I recall once said that intuition and logic are both tools not ends in themselves. Thus I think that intuition doesn't need to be logically justified because it is a different tool than logic. If people's intuition clashes, we can rely on logic from that point to see which makes more sense. I think this is how most people operate anyway without thinking about it and it seems to work for the most part.