> that nearly every professional philosopher (particularly in ethics) disagrees with this position.
So you are (at least partially) defining ethics by the consensus of people (in your case professional philosophers).
Even in pure mathematics, which is considered to be among the most rigorous of fields, a whole lot depends on consensus about axioms and consensus about what is a valid proof.
Yes, I agree there are logical principles for determining ethical actions given a set of ethical axioms, but however, the ethical axioms themselves, and indeed the logical principles, are determined by consensus.