Paul,

Thanks for the clarification.

I submit that's enough to constitute all the knowledge we need to say that kind of behavior is immoral.

So we're saying what we think is moral based on our knowledge. I'd say that's pretty watertight. We know what we feel is right, but the more we can tie it to objective facts about the world, the stronger our position. However, I'd still argue that we can never move beyond merely believing in our morals, by definition. (Yes, I said it!) The moment we state that we know that our morals are true for all time and space, we're setting ourselves up for a fall that we can't recover from.