Basically, bodybuilding is concerned with aesthetics, while the strength sports are concerned with performance. When I train, my motivation comes from the challenge. Can I deadlift 405 for 5 reps? Can I hit a new personal record of 435? It's a question of raw capability: what are the limits of what I can do? When you get into high rep rangs with compound movements, it becomes an issue of anaerobic endurance: can I squat 235 for 20 reps, or will the pain and exhaustion be too much?
This came up a few weeks ago when I was discussing a ray tracer with a classmate in the locker room and everybody else in the room had something to chip in. I wouldn't even expect that programmer-density on campus, never mind a gym 30 minutes away.
I've always heard the problem solving aspect put forth as to why it's so popular with these types.
Sounds like a great place for networking.