I feel a rant coming on!! [About Cutting]

Cutting. Why do people do it?? I've heard diffrent from everyone. "To show inner pain.", "Its an addiction.", and a bunch of other stuff. One thing is for sure, cutting is an addiction, and like alot of other addictions, it can be fatal. Two of the closest people in my life used to cut. It was an addiction. There was no diffrence between what both of them did. They both said it was bad coping skills. They both knew I knew what the real reason was. Its a fad. And it sadly turned into an addiction. I know the shit they both went through in their lifes but still its not a reason. I was always there for them. I always listened. Its not like I compleatly ignored them, I would blow off some of the most important things to me to be with them, so why'd they cut?? It's a fad. They were both in the 'emo' scene. They both cut. Coincidence?? They both admitted to it. I just dont understand why someone would do that to themselfs. Can someone who has/does cut explain it to me??