It is abnormal, it impairs normal functioning of a human being. So it can be classified as a disease.
It doesn't actually impair normal functions though. Not all members of a species specialise in the same thing, and it is okay that some do not specialise in breeding.
I actually think some people are just born wired that way. That behavior is normal for that particular individual. And it's no one else's business.
Exactly. People confuse average behavior with how individuals should behave.
