If the standard you use is wrong, no matter how well you use it in figuring out what to do, all the moral judgements that follow from it will be wrong.

I mean that what Matt said has "objective" in there but not in the way that matters. It doesnt address the issues with not having a good way of getting at whats right.

(Obv. this isnt to say that I think e.g some utilitarian approach focusing on wellbeing is wrong, its only the other bit I dont agree with)