When they came through the arrivals gate at John F. Kennedy Internationl Airport in 1968, my parents could have been seen as a threat.

It was the middle of the Cold War, and my parents — my mom was 21 and my dad was 23 — had spent their entire lives behind the Iron Curtain in a communist country. And 1968 was the bloodiest year yet for American troops in a war being fought to contain communism. Nearly 17,000 Americans died that year in Vietnam.

And here came my parents through the airport gates in the middle of all of that, in the fanciest clothes they owned, two people with paperwork — Czechoslovakian passports — that linked them to communism.

They were not detained, they were not questioned. They were allowed into a country symbolised by the Statue of Liberty.

That was the America of 1968. It is not the America of today.

My parents watched this weekend, horrified by the scenes unfolding across this 2017 America, as people like them — refugees with nothing more than suitcases and dreams — were treated so differently when they walked through those airport gates.

It was the second weekend of Donald Trump’s presidency, and, once again, he had generated a wave of protests in Washington and around the country. This time the outrage was aimed at his decision to sign an executive order banning immigrants from seven predominantly Muslim countries from entering the United States.

Trump’s Muslim ban, basically.

At the White House, up Massachusetts Avenue to the Islamic Centre of Washington, outside the Trump International Hotel and at airport arrival gates across the region and the nation, thousands of people gathered to show support for refugees, green cardholders and even American citizens who were suddenly banned from America.

My mom imagined what might have happened if, back then, President Lyndon B. Johnson had signed an executive order banning all citizens of communist countries from entering America.

A chunk of Americans would have bought that, for sure. Fear sells. Communists were the enemy. But reason, empathy and humanity won.

Because when my parents left everything behind in Czechoslovakia, when they got green cards and when they raised their hands to pledge allegiance to America, the immigrants of my parents’ era were seen as dissidents, heroes, even.

Of course, it helped that my mother and father are white and from a Christian country. And it helped that our confrontations with communism did not take place on American soil, for the most part. So they were celebrated for rejecting the enemy and embracing America.

America 2 Communism 0. USA!

This weekend, we became a country that detained a five-year-old boy from Bethesda, Maryland, at Dulles International Airport, kept him from his Iranian-born mother for hours to make sure he was not terrorist threat.

Artiman Jalali was born in the US and has dual citizenship with Iran. He was travelling back from visiting relatives with his 25-year-old cousin. Both were detained.

His mother, Shohreh Rahnama, said she waited for him for hours, until he and his cousin were finally released at about midnight. “He was hungry and he was thirsty, and I could not see him,” she said.

“How can a five-year-old be banned? Just because his parents are Iranian? We are American, too,” she told my colleague, Michael Alison Chandler, at a protest outside the White House. “I almost died in that airport. I can say it was the worst day of my life.”

We became the kind of place that treated Hameed Khalid Darweesh, who had a valid US visa and worked as an interpreter for the US Army in Iraq, like a criminal when he flew into JFK airport.

Overnight, America reneged on promises of citizenship and sanctuary to hundreds of people — translators, engineers, IT specialists, fixers. Some of them risked their lives for our military.

A friend of mine who has worked in Afghanistan and Indonesia was stunned by this development. Over time, he has helped five people come to the US from Afghanistan — all of them risked their lives helping to fight terrorism in their home nation and in turn, he helped them to find new lives in the US.

He marched on Sunday, and as the crowd went past the Islamic Centre of Washington, a woman handed out water bottles to the marchers and thanked them for their support. One of the marchers hugged her.

“And she buried her head in [the marcher’s] shoulder and began crying about how scared she is,” he said. “It is tragic to see the human toll on people who are already part of the fabric of America.”

This executive order is a shameful stain on our country, yanking the American dream out from under families who have been here for decades and from families in dangerous parts of the world who sold everything and endured years of vetting to join us.

Why a sudden executive order? To stop terrorism, Trump said.

“There is nothing nice about searching for terrorists before they can enter our country. This was a big part of my campaign.” Trump tweeted yesterday morning. It was wrong as part of his campaign, and it is wrong now.

America knows better than this.

• Petula Dvorak is a columnist for The Washington Post’s local team who writes about homeless shelters, gun control, high heels, high school choirs, the politics of parenting, jails, abortion clinics, mayors, modern families, strip clubs and gas prices