NASCAR driver Tony Stewart had strong words for San Francisco 49ers quarterback Colin Kaepernick, who has chosen to sit during the the national anthem as a form of protest over the treatment of “black people and people of color” in America.

Stewart tweeted out his thoughts and called Kaepernick an”idiot”, among other choice words.

“I’m sorry but @Kaepernick7 needs to learn the fact about police before running his [expleative]mouth! He has no clue what they go thru! #idiot,” Stewart tweeted.

Kaepernick has faced harsh criticism from fans and athletes over his stance and Stewart’s reaction is just the latest in a long line. Earlier on Monday, Kaepernick’s former coach Jim Harbaugh said he took exception to the “method of action” the QB used in his protest.

Speaking to reporters at length about his decision, Kaepernick didn’t back down from his position.

I mean people are dying in vain because this country isn’t holding their end of the bargain up, as far as giving freedom and liberty and justice to everybody.

Here are Kaepernick’s thoughts on why he’s choosing to sit during the national anthem.

I am not going to stand up to show pride in a flag for a country that oppresses Black people and people of color. To me, this is bigger than football and it would be selfish on my part to look the other way. There are bodies in the street and people getting paid leave and getting away with murder.

Twitter users were quick to flood Stewart’s mentions about the pending civil suit he’s facing in the death of Kevin Ward Jr., which Stewart also fired back against.