Is there any such thing as absolute morality?

The more I look at the nature etc. it looks like there is nothing such as good/bad etc. Each person actually lives to the best of his knowledge and understanding at every moment. The problem is not of morality etc., it is simply ignorance and the state of consciousness.

For example: Take the case of a man killing another man in society. People call it murder and probably place it as something that is supposed to invoke the most guilt.

• What if we study the neurobiology of the person who murders? 
• What would you do if you have to choose between killing yourself and another human? 
• What is you are brainwashed from childhood in a way that your goal is to kill people from the neighboring nation and that is the greatest thing you can ever do? 
• We kill all kinds of insects, is that not murder? Just because society doesn't consider it wrong?
• Hunting is legal for people who have license and its a crime for those who do not. Isn't that killing too?
• If a man kills someone, he is executed by society, isn't that a counter murder? 
• When war is launched against some country the military is authorized to kill the soldiers from another nation, isn't that killing?

The more I analyze it, the more I feel, morality is just a construct of society. Society has a law system to get rid of outliers who do not fit into the system and challenge its values such as security. Society I guess was primarily created for humans to live together in harmony. But while defining your own morality and to gain deep understanding, this is something you need to aware of.