Why do psychologists prefer the phrase "maladaptive behavior" more so than normalcy?

Maladaptive Behavior can be simply described as a quick reaction/response to abnormal and changing circumstances around them, which inhibit their ability to adapt and adjust properly.

Maladapative behavior can result in non-productive and often unhealthy outcomes for the individual. 

For example, if someone has gained weight, a positive response would be to start eating less and going to the gym. However, a maladapative behavior would be to panic, become stressful and even lead to depression.

Physiologist now use this expression more often than normalcy because in the last 2 decades there has a been a surge in the study of human behavior and research has found now common maladapative behavior is now it can have an unhealthy impact on our lives.