The reason I avoided using the term 'social construct' to describe morality is because of the connotation it has acquired in arguments where it is used to mean "meaningless." However, I ultimately believe all intangible concepts are social constructions. In my opinion, there exists a tangible universe with objective properties and intangible concepts are merely mental schemas used by our three pounds of brain matter to simplify the complexity inherent in the natural world. I am not saying that social constructs are meaningless like your argument presumes. People give social constructs meaning. Social constructs are convenient ways to make sense of reality and communicate ideas. Do you acknowledge that in a universe devoid of life, it would make no sense to discuss moral dilemmas? That is because social constructs (intangible ideas) only make sense in the context of an observer who projects such concepts onto the natural world. The early universe prior to the formation of stars was inhospitable for life and consisted mainly of hydrogen, deuterium (a hydrogen isotope), and trace amounts of lithium. Sentient life as we know it requires heavier elements such as oxygen and iron (found in hemoglobin) which are created by stars during nuclear fusion. The early universe prior to stars was devoid of biotic matter and sentient life. It doesn't make sense to discuss moral dilemmas in a universe that consists of abiotic matter that is oblivious to the universe around it. It is for this reason that morality can be thought of as a 'social construct.' It does not exist in the material world because it is intangible. By the way, you are right. Physical health is an intangible concept as well. That doesn't make it meaningless. It is a misnomer to assume that social constructs are meaningless.