A presidential inauguration is supposed to be the peaceful transfer of power from one president to the next. It’s a time when Americans welcome our next commander-in-chief and wish him well in all that lies ahead. Unfortunately, a large and growing list of Democrats won’t be attending Donald Trump’s inauguration, and this childish behavior is not only uncalled for, it divides our country even more.

Congressman John Lewis, the legendary civil rights activists and representative from Georgia who has served since 1987, is one such example. In an NBC News interview, Lewis said the president-elect is an “illegitimate president” and believes that there was a conspiracy on the part of the Russians and others to help him get elected, even though he has no proof to back up this statement. As a result, he is going to boycott the inauguration.

Shame on Lewis, one of the original 13 freedom riders who fought so hard for the black movement and equality, for making such derogatory comments towards our next president. I know Martin Luther King Jr. probably wouldn’t have voted for Donald Trump, but he would have attended his inauguration. He’d be ashamed of his friend and colleague Lewis.

Lewis isn’t alone, unfortunately. Filmmaker Michael Moore is organizing a pre-inauguration protest in front of Trump International Hotel and Tower in New York. He’s asking other celebrities to join him. Even some Hollywood lefties like Sally Field and Keegan-Michael Key have released videos targeting anti-Trump supporters to sign a petition to be sent to members of Congress to stand up to Trump.

Boycotting Trump’s inauguration and holding protests outside his hotel is childish and accomplishes nothing. Imagine if your child plays in a football league. His team loses a game. Would you encourage him to line up and shake hands with the members of the other team? Or would you tell him that it’s OK to be a sore loser and stomp off the field, go home whining about it and not congratulate the other kids on their victory? These Democrats who aren’t attending the inauguration and the celebrities who are making a stink are no different than those kids who would run off the field without congratulating the other team.

Trump being elected is bringing tremendous optimism in America right now. The stock market is soaring. Interest rates are rising. It’s like nothing we’ve seen since before the Great Recession. It’s unbelievable to think that some Democrats still can’t get past the agony of defeat. To them I say grow up, stop acting like babies and get over it.

President and Michelle Obama will be there. Bill and Hilary Clinton will be in attendance. George H. W. Bush can’t attend due to health reasons, but sent Trump a personalized letter wishing him the best. That’s a class act. That’s etiquette. That’s something these Democrats protesting and boycotting the election could learn from.

Whether you like Trump or not, he’s going to become our 45th president and there’s nothing anyone can do to change that. Rather than acting like a child who kicks and screams when he doesn’t get his way, it’s time for all Americans, including Rep. John Lewis and all the other protestors to show some respect. After all, America is stronger when we all work together.

Steve Siebold is a psychological performance coach and critical thinking expert. He is the author of “177 Mental Toughness Secrets of The World Class” and “Sex, Politics, Religion: How Delusional Thinking is Destroying America.”