Is morality objective or subjective?

[Nanny]

But though I'd really like to think that my own moral stance has a pure evolutionary background... 

Why would you like to think it has pure evolutionary background?  Do you not view yourself as an individual?  What makes you think linking your behavior to a species survival is the way to go?

This is my amalgamation of my reading and thoughts about this. Wish I could cite the sources correctly. 

Humans evolved as wanderers, hunter-gatherers, with behaviors that evolved from the pressures of the environment. Early humans learned behaviors that exploited their advantages in their environment. 

Then something changed. That something was agriculture. This allowed for sedentary populations with surplus resources. Humans began to specialize. Not everyone had to gather food and the population grew. Humans evolve behaviors to adapt to this new environment. Things like laws, writing, currency, caste, religion came to be. These are products of the evolution of human behavior in the "town" environment, in close proximity to others but with ample resources.

I don't think anyone disputes that evolution by natural selection includes behavior. 

I can swim because of my evolved behavior.  I have a breath-hold reflex from birth, but I can also maneuver freely in water. Both are products of the evolution of our species.

I do think that big M Morality - in the sense that a social group agrees to what is right and wrong - is an evolved social behavior. The downside is that differences lead to conflict among social groups. This is what I wish I could erase from our evolutionary history.

Edit for tl;dr we evolved culture. Morality is cultural. This leads to conflict between cultures. That stinks.