We’re a few steps past that. I am explaning why thing are inherently moral or immoral, not why we should or would do them (or not).
I actually think you’re conflating those two questions. Why we should do something is different than why we would do something.
We should do what’s right because that’s inherently good.
We would do what’s right because we feel that we should, and feel good doing what’s right. This type of benefit, though is not the ??? referred to in ??? ?? ??? ???? ???.