It's funny he refers to himself as "the leader of the team." That's his problem- he thinks he's the best player on the team. If he was unselfish he would realize that Lin made the Knicks better than he ever did.
You have to remember the Knick's were bad. Carmelo was bad before Lin showed up. He seemingly was overweight at times. The Knick's were out by a few games from the last playoff spot. Carmelo was being highlighted back then. That is when it started.
I honestly can't remember. Well it was worse than I thought. But you are correct that the selfish thing goes way back before Lin.
One thing about Melo, is that he actually believes in everything he says. Like he's the leader of the team; like Michelle Obama is a Melo fan (btw, the president himself wants to play one-on-one with Lin - Melo would be so jealous if that happens); like he had nothing to do with D'Antoni's departure; like no one ever called himself selfish before; like he's the victim of all the dramas involving him...
Also, the terms often used to describe Melo are "ball stopper" and "ball hogger". He doesn't know they can be interpreted as "selfish".
I just wanted to point out a few quotes from this article: http://www.mercurynews.com/jeremy-lin/ci_21139356/jeremy-lin-exclusive-i-will-always-have-haters We are BLESSED to have this young kid on our roster.