> We have consensus on basic ethical norms

On some, but morality has not been resolved, not even close.

> isnt it possible to identify which courses of action/inaction (regardless of bent) lead to ethical outcomes

No, figuring out all the consequences of a given action quickly gets intractable the bigger the action is. You can make predictions as to the effect of a law or policy, but you usually can't make guarantees as to their effects. nth order effects keep piling up.