was he acting like a sore loser?
http://www.nydailynews.com/news/national/king-super-bowl-50-highlights-racial-double-standard-nfl-article-1.2524445
With time still remaining on the clock, Peyton did something that Cam Newton (or any black quarterback for that matter) would have been absolutely skewered for he left the field.
He didn't congratulate the opposing quarterback Drew Brees, as is customary. He didn't shake any hands. He didn't try to smile. He just bailed.
Here's how Chris Chase, of Yahoo Sports recalled it in an article entitled, "Peyton Manning storms off Super Bowl field. Is he a poor sport?"
"Peyton Manning didn't shake hands with New Orleans Saints players after his Indianapolis Colts lost 31-17 in Super Bowl XLIV. Apparently some think this is a sign of poor sportsmanship from the NFL's greatest player. It's not. Walking off the field without congratulating Drew Brees may go against our misguided notion of what sportsmanship should be, but it wasn't at all disrespectful or bitter. It shows how much Peyton Manning wanted to win the game. And who can argue about that?"