I'm not a team sports tv watcher or supporter but my take on those who are is that it satisfies a need for a 'tribal identity'. For showing a steadfast loyalty to their 'tribe' through thick and thin, through victory and defeat. And thus I'm not surprised at their level of emotional involvement, and vicarious 'capture' even through a tv screen.
Discussion
Oh I get that it's the modern-day gladiator arena, its being able to attach yourself to a group, to feel the emotions of winning and losing without having really anything at stake, but some people get way too attached to this simulation, its as if they're really on the field making a difference