There are (at least) two meaning for “why ought we be moral”:
“Why should an entity without goals choose to follow goals”, or, more generally, “Why should an entity without goals choose [anything]”,
and, “Why should an entity with a top level goal of X discard this in favor of a top level goal of Y.”
I can imagine answers to the second question (it could be that explicitly replacing X with Y results in achieving X better than if you don’t; this is one driver of extremism in many areas), but it seems clear that the first question admits of no attack.
Me, too, but about two years ago. Unfortunately, I’ve had a hard time liking wine, so I’m hoping that moderate amounts of scotch and/or rum have a similar effect.