AP Photo/Jae C. Hong

It was widely presumed that American sprinter Justin Gatlin was booed during the 100-meter final Sunday night because of his history of doping and his serving of two bans on that front.
 
There may have been another reason: Quite simply, he wasn't Usain Bolt.
 
Boos were resounding around Olympic Stadium when Gatlin walked out for the final, and even Bolt _ the crowd favorite in Rio, as he is in just about every other track stadium in the world _ was surprised by the amount of negativity.
 
"Free expression, I would say," International Olympic Committee spokesman Mark Adams said Monday.
 
Rio Games organizing committee spokesman Mario Andrada went even farther, pointing out that most fans were just pro-Bolt.
 
"I think that it was very clear from the beginning that the crowd had a favorite for the race," Andrada said. "Not all the crowd was booing because of Mr. Gatlin's past. A lot of people were booing because he was the opposition to the chosen idol for the night."
 
Bolt won the gold, while Gatlin took the silver. Gatlin said he wished the crowd had been more respectful, and Bolt tipped his cap to his American rival afterward.
 
"I personally think he's a great athlete," Bolt said. "He shows up and pushes you to run fast and be at your best at all times."