What I think is ridiculous is this idea of "Fandom". I root for 1 team, the Patriots. Other than that, I'm a fan of football. I personally find Fantasy Football as another way to enjoy the sport, it gets me involved and gives me excuses to watch stats, watch games, and root for teams/players.
I do keep Fantasy football in check, though. I have 2 Colt players on my team right now (Collie and Clark), but I put them both on the bench and looked for the best waiver wire pick-up for the week. I mean, it's really simple. If you don't want to root against your team, sit those players facing your team. No one is forcing you to start them. Heck, even if I had Peyton Manning on my team, I'd bench him this weekend, even if that meant settling with a Sexy Rexy QB. It's all about the fan.
Other than that line, I enjoy Fantasy Football. It's just something to keep you involved. Honestly though, I think Money might very well be the best reason to root for a team. "Fandom" doesn't really mean anything, putting your money where your mouth is, does.