You can pretend that morality is simple and agreed upon all you'd like, but it won't make it true.

Agreed upon? Objective reality does not depend on anyone's assent. You can pretend that 2 + 2 = 5, but that does not change objective reality. Just like if you pretend that child molestation is moral, it doesn't make it so. Sorry!

I could postulate quite a few scenarios of "justifiable murder",

Right... but that's not the question, murder itself it. The whole idea of 'justifiable murder' rests on the belief that murder in general is immoral, something you apparently deny. Because if morality is subjective, someone can declare murder to be moral and you cannot call him wrong.

My response was in regards to your comment about "psychological biases that lead people to affirm stupid mistakes they have made in the past" which implies that you're assuming she is justifying her actions

As I said before, that is an argument against basing moral judgments based on what people say about their subjective feelings.

Um, he was?

In this particular case?

Again, you're assuming she was conned.

Do you "arguments"? Do you know what an analogy is? Please do look it up. The point is that her subjective feelings about it do not matter, just like a victim of a con is no less a victim of a con, simply because he feels that he has not been conned. Address the argument, instead of inventing one.

Actually yes, I think that's what you're doing. Oh, sorry. Society is on your side. That's why they're objective. How silly of me.

He said, right after I told him that what "society" says doesn't even matter. You know, if you're going to lie and misrespresent everything in every single post, then I think a productive discussion is out of the question.

But... there is no truth! How silly of me! Nothing is a misrepresentation, because everything is subjective. If you "feel" that "I don't like energy drinks" means "I love genocide", then you're not objectively wrong! It's a perfectly valid interpretation!

Oh, look, a person defending the objectivity of morality with a 100% subjective argument.

It was not an argument, it was a comment. Learn the difference. It's funny that you contradicted your own moral relativism in this very comment. Relativists can never take their beliefs to their logical conclusion.