Hermes, thanks for following me around! ;-)
I should have phrased my point better: of course science, not just neuroscience, informs ethical decisions. After all, ethics deals with the real world, so we need facts. I am resisting, though, what I see as a prescriptive streak coming out of neurophilosophy. A given set of facts about the brain does not unequivocally pinpoint a single adequate ethical line.
Also, several of your examples aren’t that convincing to me. Did we need to discover the effect of oxytocin and vasopressin on cooperation to decide that it is better to cooperate? No, though it’s a nice plus from a scientific perspective.
The beneficial effects of cannabis aren’t a discovery of neuroscience, but of medicine and psychology. And neuroscience still tells us little about schizophrenia and paranoia, but we have treated them as diseases for a long time, on the basis of psychological research.
In other words, the “neuro” level, while certainly interesting and informative, is not any more crucial or informative than other levels of description. It depends on what we need to know.