The Hobbesian view of human nature has been successfully challenged, on both philosophical and evolutionary-anthropological grounds, way before the discovery of oxytocin. Which, as you say, also promotes xenophobia. A perfect case of how neuroscience is descriptive, not prescriptive.
Of course neuroscience discovers receptors, that wasn’t my point. Much of the kind of factual progress we have made that is relevant to ethics has come from medicine and psychology, as well as anthropology and evolutionary biology. Again, levels of description. There is nothing more fundamental or epistemically primary about neuroscience.
Same for your point about curing schizophrenia. My point wasn’t about where a cure will come from, if it will. It was about knowing enough about the condition to consider it a disease. For that, we didn’t have to wait neuroscience.
With all due respect to science, and to the occasional cross-disciplinary success stories (including from your lab), the trend has actually been of increasing divergence and specializations between fields. Which is why I think philosophy of science, and event so-called scientific metaphysics, play a role: in integrating the various pictures emerging from the special sciences. See the work of Jerry Fodor, but especially of Wilfred Sellars: The most important philosopher you never heard of.