Is it true that there is no absolute morality?

[Angrboda]

Okay.  I talked before about the subjective agency which establishes a limited context in which SOME things can be said to be true: "It is true that I like chocolate better than strawberry ice cream."  Opinions are not subjective truths in any sense more than that.  But none of this changes the fact that humans are moral animals and worms are not, and that this is because of a genetic inheritance that predates, and therefore is objective to, the individual (or even plural/cultural) existence of human beings.

It's true that humans are moral animals because of our DNA, however our DNA does not constitute a moral system in the same sense that the design of an automobile does not constitute a car. Thus if DNA is objective or not is irrelevant.

But I more recently distinguished between two definitions of "morality" that I felt could put this conversation to bed.
1)  A system of ideas about what represents right or wrong, and about behaviors which represent them.
2)  The capacity or tendency to have a sense of right or wrong, and the motivation to act accordingly.

The former, which I think you are talking about when you talk about opinions being variably true or not true, is most usefully described in subjective terms.
The latter, which is ingrained in us at a genetic level, and which has been studied in animals not capable of forming linguistic ideas or holding "opinions," is most usefully described in objective terms.

No. The brain functions which comprise the thoughts of morality are still subjective, whether they're viewed in terms of blood flow and fMRIs or not because they are the thoughts and opinions of a subject, just viewed in a different form. You don't get from subjectivity to objectivity simply by changing viewpoint; objectivity means you are completely outside the loop of internal mental events, whether they are viewed as blood flow or as thoughts. Perhaps you mean the latter is most usefully described third person, but that's not the same as objectively.

I would still argue that the former is also more accurately described as objective, but I can also see that it is pragmatic in talking about our experience of subjective agency to see people as active agents, rather than passive observers of brain function that isn't actually under our control.

And I would argue that you're still confused about the meaning of objective.