Hall of Fame coach Mike Ditka has leveled blistering criticism at Colin Kaepernick’s decision to kneel during the national anthem, saying he has “no respect” for the San Francisco 49ers quarterback whose protest has sparked a national discussion over racial injustice, inspired dozens of NFL players to follow suit and landed him on the cover of Time magazine.

“I think it’s a problem, anybody who disrespects this country and the flag,” the longtime NFL coach said in a radio interview on KRLD-FM in Dallas. “If they don’t like the country, if they don’t like our flag, get the hell out. That’s what I think.

A kneeling Colin Kaepernick appears on the cover of this week’s Time magazine. Photograph: Time Magazine

“I have no respect for Colin Kaepernick. He probably has no respect for me, that’s his choice. My choice is that I like this country, I respect our flag, and I don’t see all the atrocities going on in this country that people say are going on.

“I see opportunities if people want to look for opportunity. Now if they don’t want to look for them, then you can find problems with anything, but this is the land of opportunity because you can be anything you want to be if you work. Now if you don’t work, that’s a different problem.”

The 76-year-old Ditka, who was inducted into the Pro Football Hall of Fame in 1988, is one of two people in NFL history to win a league title as a player, an assistant coach and a head coach. He graduated from local hero to Chicago icon during an 11-year coaching stint with the Bears that included the team’s only Super Bowl win during the 1985 season, then retired permanently after a failed comeback with the New Orleans Saints in 1999.

A well-known conservative, Ditka publicly flirted with running against Democratic candidate Barack Obama, then a state senator, for the open seat in the US Senate vacated by Illinois senator Peter Fitzgerald in 2004. No one then could have imagined how the election would ultimately propel Obama to the presidency in four years’ time.

“Biggest mistake I’ve ever made,” he told the Dickinson Press in 2013. “Not that I would have won, but I probably would have and he wouldn’t be in the White House.”

In March, Ditka called Obama “the worst president we’ve ever had”.

“Barack Obama is a fine man,” he added. “He’s pleasant, he’d be great to play golf with. He’s not a leader.”