It's his job to make people watching the fight get excited. The fight started to get close. Rogan hyped it up. Calm down.
People can get excited from commentary that isn't pretty much screaming "Edgar still has it, he'll lose tonight but scream and shout and pout that he deserves a rematch after three straight losses!!!"
Honestly, Rogan's commentating is so horrendously biased sometimes that I have to mute the TV. I found myself yelling more at Rogan than either of the two fighters this match. Not that that matters, since I was just yelling at my TV, but you get what I'm saying, right?