I do realize now I accidentally shifted the language from "universal" morals to "objective" morals. If a moral principle is claimed to be universal, it must, by definition, be applicable to all possible scenarios.

An objective moral isn't invalidated by an immoral choice still being the most correct choice in a set, but a universal moral is invalidated by only a single exception.

I suppose it's up to you if you were agreeing with the OP on the choice of "universal".