An athlete steps over the line of good sportsmanship after a game, yells into a microphone held by a pretty sideline reporter, gloats, mocks, plays the role of ugly champion to a tee and immediately is crushed in the world of social media.

In another city, a coach attacks the character and professionalism of an opposing player, accuses a 5-foot-9 wide receiver of intentionally trying to injure somebody, calls it, “one of the worst plays I’ve ever seen” — insert laugh track — and is subjected to only mild criticism.

Richard Sherman: You’re free to go.

Bill Belichick: Stay right there.

This isn’t to suggest that Sherman, the turbo-lipped Seattle cornerback, didn’t deserve criticism for his ramblings and antics following the NFC title game against San Francisco. He was immature. He said stupid things. He did some stupid things. He got lambasted. He apologized.

Story over … please. This thing mutated from amusement to cyber assault to burnout in roughly an hour.

What Belichick, the New England coach, did Monday the day after the Patriots’ AFC title loss to Denver was far worse than Sherman. He deserves far more scrutiny and more criticism. Where’s the outrage?

Belichick was upset because Denver wide receiver Wes Welker knocked Patriots cornerback Aqib Talib out of the game on a pick play. On Sunday, he called it “a key play in the game.” (Personally, I’m thinking when a defense gives up 507 yards, that play is more like a cameo. Also, the pass on the play in question was incomplete.)

On Monday, without prompting from the media, Belichick shifted into full assault mode. His opening statement included these words: “I think it was a deliberate play by the receiver to take out Aqib; no attempt to get open. … It’s one of the worst plays I’ve seen.”

Belichick has coached in the NFL for 39 years. He was a defensive coordinator for the Patriots, the New York Giants and the New York Jets. But THAT was one of the worst things he’s ever seen?

Bill Belichick just redefined disingenuous. The man coached Rodney Harrison.

I’ll yield to the words here of former Patriots wide receiver Donte Stallworth, who took to Twitter after hearing his former coach’s comments: “I have nothing but love and respect for Bill Belichick, but he’s absolutely wrong about Wes Welker’s hit on Aqib Talib… and he knows it.”

Stallworth followed that up later with this message: “‘Sometimes people don’t want to hear the truth because they don’t want their illusions destroyed.’ — Friedrich Nietzsche.”

Right. The Lord Belichick could not possibly do any wrong. He has won Super Bowls. He is in the greatest-coach-of-all-time debate. So when he says something so calmly in a news conference, even if it borders on slander, it must be true, right?

Belichick would never admit this. But there are two things that really fueled his attack: 1) The play, which is common in the NFL and in fact was perfected by the Patriots, happened to his team. If a Patriots’ receiver had knocked out a Broncos’ defensive back, we never would have heard a peep from the coach; 2) The central antagonist was Welker, who used to play for New England. Welker left after last season when Belichick chose not to re-sign him, and he’s a big reason why the Broncos are going to the Super Bowl and the Patriots aren’t.

I’m not excusing what Sherman said or did. I don’t like when an athlete gives the choke sign, as Sherman did to San Francisco quarterback Colin Kaepernick after the game. I don’t like when somebody explodes with a, “Look at me” moment in a postgame interview. I’m kind of old school in that way. Even if Sherman felt disrespected by 49ers wide receiver Michael Crabtree, just win the game and move on and let Crabtree wallow in his misery.

But Sherman is an emotional player and what he said was far more in the heat of the moment.

Belichick was calculating. Also petty. The day after the game, his ego still wounded by a loss, he lashed out at a player who, frankly, made him look stupid.

The day after the San Francisco game, Sherman apologized.

The day after the Denver game, Belichick attacked. He basically called Welker dirty. I watched the replay, too. Welker’s hit was mild compared with others I’ve seen. Ask Tom Brady if his mediocre group of receivers could get open without pick plays. (Julian Edelman did the same thing to a Broncos’ defensive back earlier in the game.)

Welker wasn’t penalized. There has been no hint from the NFL of any disciplinary measure, nor should there be.

Sherman took his lumps. Let’s move on. Belichick is the one who should be skewered. Or would his words have caused a greater uproar if he had said it to Erin Andrews after the game?