UPDATED with video: Stephen Colbert kicked off his week on Late Show trashing Donald Trump’s decision to attack NFL players taking a knee during the national anthem at last Friday’s base-baiting campaign rally in Alabama.

“For the last year some NFL players have been kneeling to protest institutional racism,” Colbert explained. It started with then 49ers quarterback Colin Kaepernick. It was a controversial protest, Colbert acknowledged, explaining the singing of the national anthem at NFL games is a sacred time when Americans rush to the toilet because that’s when the line is shortest.

On Friday, Trump addressed the controversy, asking his base if they’d like to see NFL owners respond to the gesture by shouting “Get that son of a bitch off the field right now – he’s fired!”

“Wow! ‘Son of a bitch’? That was unnecessary roughness!” Colbert reacted. “There should be a flag on that play, and I’m going say a Confederate flag.”

The blowback was immediate; Kaepernick’s mother, for instance, responded, via Twitter: “Guess that makes me a proud bitch.”

Colbert pronounced Kaepernick’s mother “The Coolest Mom In Sports.”

Since then, NFL teams released statements supporting the players. And, by Sunday, the number of protesters had gone from fewer than 10 to more than 250. “Which is great for anyone with a fantasy racial justice league,” Colbert snarked.

Demonstrations took many forms during Sunday’s games, including locked arms on the field during the anthem, to more kneeling. In response, Trump tweeted that locked arms were good but “kneeling not acceptable” predicting “bad ratings.”

First of all, it doesn’t mean they’re on your side,” Colbert explained to Trump of those who locked arms. “And, second, ratings aren’t the only indicator of importance. I hear nobody tuned in for the Revolutionary War.”

The next morning Trump still was tweeting on the subject, insisting “The issue of kneeling has nothing to do with race.”

“Wrong!” Colbert corrected POTUS, hours later.

“Kneeling during the national anthem has everything to do with race. Just like your presidency.”

Then the late-night host spelled it out for Trump: Those kneeling players are protesting racial injustice, not the American flag, adding, “You do realize that the civil rights activists weren’t sitting at the lunch counter for better grilled cheese?”

During his rally, Trump also had complained football today isn’t violent enough, saying “Today if they hit too hard right – 15 yards, throw him out of the game…”They’re ruining the game, right!?”  Colbert translated Trump’s message: “There is nothing wrong with brain damage…I mean look how far I got!”

But, Trump had then simpered that the No. 1 reason NFL ratings are down “massively”  is “they like to watch what’s happening with Yours Truly.”

That’s “an Inverted Tom Brady” play, Colbert said: “Trump is trying to inflate his own balls.”