"I think it has to do with a little bit of arrogance and also, I hate to say it this way, possibly the color of your skin playing quarterback," Smith said Thursday on "The Dan Patrick Show." "I think it does."
"Automatically people started calling him a thug," Smith said. "They don't call Aaron Rodgers [a] thug. They don't call other guys of other colors thugs, but as soon as an African-American athlete does it, they say, 'thug.' "
Smith played three seasons with Newton (2011 to 2013), catching 216 passes for 3,313 yards and 15 touchdowns. He joined the Baltimore Ravens in 2014 after being cut by the Panthers.
He described Newton a "new-age quarterback."
"He throws the ball, he runs the ball," Smith said. "And kind of like [Colin] Kaepernick was in the Super Bowl with the Baltimore Ravens versus the 49ers, he brings an element that you cannot account for."
Smith added: "Really, I think the underlying story of this Super Bowl is the old, traditional gunslinger versus one of the new-age gunslingers, who brings another element that genetically -- I hate to say it this way -- but Peyton Manning has never had. He is changing the quarterback play as we know it."