The lieutenant commander-in-chief of the Sons of Confederate Veterans -- yes, that's a thing -- is taking full responsibility for the Confederate flag that flew over Talladega Superspeedway on Sunday.

"During and before the start of the NASCAR race in Talladega, Alabama, race, our plane flew a banner announcing a drive to 'defund NASCAR,'" Paul C. Gramling, Jr. told the Columbia Daily Herald.

The head of the SOCV says the group strongly believes NASCAR's new Confederate flag ban is simply unconstitutional ... and they're clearly very bothered by it.

"NASCAR's banning the display of the Confederate battle flag by its fans is nothing less than trampling upon Southerners' First Amendment Right of free expression,"

"This un-American act shall not go unchallenged."

May we add ... boohoo, crybabies?

Despite the backlash, NASCAR isn't budging on its ban -- which has been widely applauded by pro racers and athletes from all sports, including LeBron James.

Bubba Wallace had been leading the charge to remove Confederate flags from NASCAR -- saying it made Black people feel uncomfortable at races because of the connection with slavery.

"No one should feel uncomfortable when they come to a NASCAR race," Wallace said.

"So it starts with Confederate flags. Get them out of here. They have no place for them."