Hi T.!
This is really a tough one! I have a son you age, then one in college as well, so I have definitely been through this.
At the age of 12, almost 13, they seem to finally have the "courage" to talk back, and speak what they really want to say. In your case ".....anything else, ever again...." Usually, it means that they are "over-worked"...tired. School just started, so there's an adjustment period he's probably going through. Bascially, he doesn't have enough time for his friends which is the most important thing right now for him.
In my house, you HAVE to participate in a Spring/Fall sport. It is mandatory, but it can be anything they choose....a sport, an instrument, or whatever. When my 12 yr old gets EXHAUSTED from his busy life, he says things like your son has said. I feel bad for him. This year, I have tried to help him develope a schedule that includes his friends daily. Whether it be an online computer game, or someone coming over for a short period of time.
There have been times when I was the one who called off "going to practice", but I had to have an excuse that had nothing to do with my son. It was because I had too much work to catch up on, or whatever. This way, when I felt lke he needed it, he had a day off of routine.
T., it sounds like he just needs a better balance with his favorite "things" .............skating & friends. Try to make sure he has those. I wouldn't let him have skating as his "sport", though. It would be too hard to "watch" him to make sure things are innocent for his age-level. At this age, they can stray really fast!
Listen to your heart...........you'll do great!
:o) N.