So he was taught early that completing the adventure was the number one priority in D&D. You want to get to the end. That means being the best at combat so that you can defeat all the challenges since they will all be very hard. It means maximizing the skills that get asked for the most often. It means not talking to an NPC unless you have the highest social skills in the party because the DM might ask you to roll them if you speak. And succeeding in that roll might make the difference between finding a magic item in the adventure or getting a bunch of bonus XP.
I love Organized Play but it can bring out the worst in some gamers. My roommate can sometimes get very angry at people for not following the "unspoken rules" of the game. Like: "All players have to take their share of the damage. Anyone hiding in the back and refusing to ever get hit is not contributing and deserves to die. After all, they are letting everyone else take the damage for them...so they are letting you die."
So, I don't entirely blame his gaming attitude on him. He was taught it by the people at our Living Forgotten Realms tables. Though, the rest of the people I know relax that attitude when we switch to home games because it is a different atmosphere. Also, they take it a little bit less seriously. If someone with a CHA of 8 talks to an NPC and rolls a 9 when a 10 was needed to get a magic item in the adventure, they'll be disappointed and probably even say "Why did you do that? Don't do that again!" but the guy in question will spend the next year in a backlash against anyone who even thinks about opening their mouth without an 18 CHA. If someone does, he'll sulk for the next 30 minutes of the game.