What was the score at the time?
4th and inches and 4th and 2 are just not comparable.
Not only that, but the Colts needed to get into the endzone to win the game. Pats D was playing fine, they had a chance to stop Manning if BB just gave them one.
BB is a great coach but that was a terrible decision, no matter how you slice it. Showed no confidence in his defense whatsoever. That can really hurt a team's demeanor and attitude.
As a head coach you can't risk losing the game unless you have to. Punt the ball and make the Colts earn 7. You aren't automatically giving them a win by punting but you are if you fail the conversion. Great teams do not need to take unnecessary risks like that when they are winning.
And whatever happened to "defense wins championships"?
Give your defense a shot at least. What are you paying those guys for? I really think that Belichick has let Brady, Moss, and Welker get to his head and he has forgotten the importance of running the football and playing defense.
It's pretty much the same thing that happens to me when I play Madden. If I use the Raiders then I make it a point to run the ball, control the clock, and put together drives while playing solid defense just to keep the game close. Then when I use the Patriots I throw 10 screens to Welker and 10 bombs to Moss and run shotgun 99% of the time and usually end up losing because I think I'm better than I actually am.