What is Abnormal Behavior?

The Sociocultural definition: Behavior is abnormal if it deviates from societies norms mores.
Advantages to this definition: It allows for smooth social interaction.
Disadvantages to this definition: It's saying conformity is normal, and there are no "sick" societies.
What brings this up? This post by the Brooklyn Wolf on Tznius. Would you say that we are heading toward a "sick" society, that needs to be healed? In places where conformity is equal to normal, anyone not from there is considered not normal and will be shunned because of the way she dresses. There is a reason psychologists don't like using that definition. It very much limiuts what could be considered abnormal, and it allows for society to dictate what normal is. And in a "sick" society, that is not a good thing.