Nice little shit at Canadians there bud, you're certainly not doing a good job representing America. He's apologized. It was most likely a heat of the moment kind of thing. You're getting mad over literally nothing.
He apologized because he doesn't want Billboard radio to stop playing Gangnam Style and cut off his royalties.
If you're mad I took a dig at Canadians, you're getting mad over literally nothing, 'doncha knohhww.'