Of all the repugnant cultural phenomena “normalized” by our current political moment, our collective inability to speak to other people with whom we disagree with respect and civility — and without flagrant use of the f-word — has got to be one of the worst.

Andy Ternay would probably disagree.

He’s the Garland, Texas, man who walked into a Richardson, Texas, restaurant recently wearing a shirt that read, “(expletive) Trump and (expletive) you for voting for him” in big black block letters on the front.

Classy.

Lots of people take issue with President Donald Trump, are affronted by his coarseness and vulgarity, and object to the hateful language and politics of some of his supporters.

But for all his criticisms of Trump, Ternay, it seems, can’t help but to respond in kind.

His message was not only gratuitous and vulgar, it was hateful and myopic. Sound familiar?

Ternay said that wearing his shirt was an effort to show solidarity with marginalized groups.

Clearly, he was trying to elicit a reaction, and he got what he was looking for.

A restaurant manager asked him to leave because his shirt was making other patrons, particularly those with kids, uncomfortable. According to Ternay’s account, which he later documented on Facebook, kids who can’t handle the f-word are going to struggle in this world.

And adults who use it apparently deserve high praise.

His Facebook post, now unavailable, was shared well over 100,000 times, including by several of my social media “friends” who were not merely approving of Ternay’s message but of the way he chose to express it.

I’m not impervious to the frustration and anger felt by many Americans in the era of Trump. I feel some of it, too.

Nor am I naive to the reality that the flames of hatred are fanned by social media, the news media and everything in between.

But I cannot understand why so many Americans on the left and the right, freely succumb to their basest tribal instincts in response, or worse — use Trump’s vulgarity and hate, or that of his supporters, to justify their own.

According to Ternay’s account, he told the manager how “explaining ‘grab ’em by the p--y’ and golden showers to my daughter was equally unpleasant,” as explaining the f-word to other patrons’ kids.

That kind of argument is akin to the unforgivable relativism by some on the right who have justified Trump’s indiscretions by pointing to those committed by Bill Clinton.

Clinton, therefore Trump. “S--hole countries,” therefore “f-- you.”

There’s cognitive dissonance for you.

Yes, anger and acrimony have always been a part of our political culture.

None of this is new. But it seems so much worse and ubiquitous today.

The anger so flagrantly hurled at anyone with whom we disagree isn’t just a retreat from civility, it’s retreat from the idea — often espoused by progressives — that we share a common humanity. We walk around every day interacting with people whose views and ideologies diverge from our own. But increasingly, there is a belief that instead of trying of engage or attempt to win them over with rational arguments and dialogue, we should reduce their humanity to a single action. A single vote.

“I retreated from my porch,” wrote Ruth Mayer, a communications consultant from North Carolina, of her new tendency to not engage with neighbors who held divergent political views. In a column for the Charlotte Observer, she recounted how she and her daughter, returning from the Women’s March in Washington, D.C., encountered a man and his son who helped them fix her car. She had spent the last year outraged with Trump and his voters. But her experience with the self-described redneck — and probably Trump voter — was a powerful sign “that maybe if we treat one another with the kindness and gratitude that is so absent from our president and his policies, putting our most loving selves forward, this moment can transform into something more bearable.”

It will be hard to do that while wearing a shirt like Ternay’s.

But if we are serious about reducing the hate the permeates our politics it has to start with our daily interactions — what we chose to say to our neighbors, on social media and on our T-shirts.

Otherwise, we’re no better than the people we criticize.

Cynthia M. Allen is a columnist for the Fort Worth Star-Telegram.