Denver Broncos head coach Vic Fangio says there's no racism at all in the NFL ... but a Seattle Seahawks star clearly disagrees -- with Chris Carson calling the guy a "joke" for the comments.

Fangio was on a conference call with reporters Tuesday, going in-depth on his feelings on social injustices in America -- when he said society needs to be more like teams in the NFL.

"We're a league of meritocracy, you earn what you get, you get what you earn," Fangio said. "I don't see racism at all in the NFL, I don't see discrimination in the NFL."

The comment quickly caught the attention of Seattle's star running back ... with Carson immediately responding to Fangio's words by saying, "This man a joke ..."

Chris -- who rushed for 1,230 yards and 7 TDs last season -- didn't elaborate ... but his 'Hawks teammate, Quandre Diggs, did ... adding, "Is he blind??"

Fangio -- who's coached in the NFL in some capacity for more than three decades -- went on to tell reporters, "We all live together, joined as one, for one common goal, and we all intermingle and mix tremendously."

"If society reflected an NFL team, we'd all be great."

Of course, non-NFL players on social media also criticized the opinion ... claiming the NFL blackballed Colin Kaepernick after he attempted to bring awareness to police brutality and social injustices in America by kneeling during national anthems.

For his part, Fangio did condemn the police officers involved in the death of George Floyd ... and he also encouraged his players to protest racial inequality in the country.