I'm not sure I follow completely but I think I get the gist. The is/ought distinction is a good way to look at it. But I think there is another distinction that has to be made. That is between an objective moral "ought" and a prudential "ought." Prudential "ought" having to do with an action being beneficial to one's goals/needs etc. but nothing more than that.

I think people like Harris build a good case for an ethical system based on prudential "oughts" but without a God, it doesn't follow to me that we have reasons for moral "oughts" which I think is what you were agreeing with if I understood correctly.

One other thing that's interesting about Harris is that he makes the claim that human flourishing is automatically good, and suffering is bad because we experience them to be either good or bad.

That argument strikes me as circular. It's like he's saying human conscious experience has intrinsic value. And how do we know this? Well, that's what our conscious experience tells us.

That's just as bad as the Bible thumper who says the Bible is the word of God and we know this because it says so in the Bible! hahaha