Good exchange. I think you both should examine this comment further. It's a bold truth claim based on ones subjective interpretation and imo is the derailer of what could have been an educational read between opposing view points.

"It's irrelevant whether you accept it or not. it is true and it can be confirmed by looking through history and cultures across the world. Your morality comes from the environment."

I would say you make a large assumption that defining morality is contained within the environment you are exposed to. I understand morality to be more based on objective truths about the nature of good and bad. Universality being at the core of that understanding. We may think good or bad about a given situation/set of actions and that may found to be flawed when we are exposed to new information. So to say "it is true" based on how "you" percieve a read of history and culture, is in fact intellectual laziness that is lacking any real desire to reach any understanding that may oppose your currently held "beliefs".