Last Friday night, when Stephanie Wilkinson, the owner of the Red Hen, decided to eject the White House press secretary from her small restaurant in Lexington, Virginia, she could not have had any idea of the row she was about to ignite. Sarah Sanders, who was already midway through her meal, was asked to leave after Wilkinson’s staff voted to eject her in protest against the president’s policy of separating children from their parents at the Mexican border.

Since then the rustic farm-to-table eatery has been at the centre of a national debate about civility and politics. And the reaction has overwhelmed the restaurant. It has been forced to close, having had eggs – and excrement – thrown at it, and it has been besieged by angry protesters. Another business in Lexington, with no connection to the Red Hen, received a bomb threat. On Saturday, scores of “Bikers for Trump” are planning to gather outside.

But, as if to illustrate the increasingly tribal and partisan nature of public life in America, the Red Hen has also been inundated with flowers, sent by people from across the US and even from Europe. Hundreds have left supportive messages on its Facebook page.

Over the last week, Wilkinson’s small, pretty restaurant in a small, pretty town has become a place that encapsulates the polarisation of American society.

Wilkinson told the Washington Post she had asked Sanders to leave because some of her staff were uncomfortable with the White House press secretary’s presence in the restaurant. Some were gay and objected to serving someone who had defended Donald Trump’s attempt to ban transgender people from the US military. The separation of migrant families at the southern border was another Trump policy discussed.

People protesting outside the Red Hen. Photograph: Adam Gabbatt/The Guardian

The national response to the incident, however, has moved beyond such concerns. Local businesses unaffiliated with the Red Hen have received abusive phone calls and emails.

On Wednesday, a group of five people – two men, two teenage girls and a teenage boy – spent three hours standing outside the restaurant, which is housed in a small redbrick building just off Main Street. They were holding handwritten signs expressing support for Sanders and Trump and waving back in response to the sporadic horn honks they inspired.

This is what happens when the leader of the country behaves like a 12-year-old Rae Stephens, Washington Street Purveyors

None would speak to the Guardian. Nor would a man who stood across from the Red Hen, holding a Bible and preaching about the ills of homosexuality. At the Washington Street Purveyors wine store, next door to the Red Hen, two employees were unimpressed with the pro-Trump protest.

“It’s just ridiculous that it’s turned into this political debate,” said Siobhan Beza. “It had nothing to do with that; it had to do with Stephanie’s employees feeling uncomfortable. The people who work there, the people that own it, they’re the kindest people.

“And now people in the county are coming here to say they hate gay people. It’s like, ‘Why are you doing this?’”

A family from South Carolina stopped by the restaurant for a photo, as did a man from West Virginia who was wearing a Trump T-shirt. Beza’s colleague Rae Stephens said their store had received abusive calls.

A man near the Red Hen. Photograph: Adam Gabbatt/The Guardian

“I actually received a call from someone in California saying may we rot in hell and that we all lose our businesses and it’s a horrible place,’” she said, “and further really horrible language from somebody who’s never even set foot in the state probably, much less been to this area.

“This is a tiny little microcosm of what’s going on in the whole country. This is what happens when the leader of the country behaves like a 12-year-old.”

‘Many, many bouquets have gone out’

Lexington has a population of 7,000. It is in the traditionally Republican south-west of Virginia but it voted for Hillary Clinton in 2016, a blue Democratic spot among all the red. Not used to controversy, it is a town where colourful knitted decorations are placed outside the library. In well-kept buildings along Main Street, businesses hang signs reminding people about a community firework show.

The response to the Sanders incident illustrates just how divisive political debate has become. Beza said people had stopped by the Red Hen to leave positive messages. As we talked, a woman arrived to place flowers on the restaurant doorstep.

The woman did not want to speak to the Guardian but it was clear she had not been the only person to show such support. About 500 yards up Main Street, the owner of University Florist, a beautiful and fragrant store with a jaunty sign and white window frames, said she had been inundated with orders.

“Many, many bouquets have gone out over the last two days,” Carolyn Tolley said. “More than a dozen. All in support of Stephanie.”

Regardless of what people believe or who the person is, service is service Owner, Niko's Grille

Tolley had received orders, she said, from Texas, New York, Michigan and Maine, as well as a flurry of requests from local residents. She showed a message she had delivered with a bouquet someone ordered from the UK.

“Congratulations on taking a stand,” it read. “London, England, admires you.”

But Tolley had also seen the ugly side of things. Like other businesses the Guardian visited, her shop had received abusive emails. A common theme was to lament the lack of civility shown to Sanders – while wishing ill to residents of the town.

More troublingly, Tolley witnessed a bomb threat that Niko’s Grille, the Greek restaurant next door, received on Tuesday. Tolley was in Niko’s, she said, when a man called. She spoke to him.

Carolyn Tolley, owner of University Florist. Photograph: Adam Gabbatt/The Guardian

“He said he was coming to Lexington and he was going to bomb all the restaurants,” Tolley said. “He said that this town was full of hate and that he was coming to take care of the town that was so full of hate.”

The restaurant closed and police intervened. Niko’s reopened on Wednesday. Its owner said he thought Wilkinson had been wrong to ask Sanders to leave.

“I think she should not have done that,” said the owner, who asked to speak without being named. “Service is for everybody, you know. Regardless of what people believe or who the person is, service is service. It’s another thing somebody causing problems in the restaurant, but just somebody coming to eat is different.”

Outside, 50 yards away from the Trump-supporting protesters waving their signs outside the Red Hen, a dreadlocked man played songs of peace on a guitar.Later, the street was empty and quiet. On the doorstep of the little restaurant, lit by yellow street light, someone had left a sign.

“Lexington loves Red Hen” was the simple message, written on cardboard. It seemed like a little symbol of hope – that people in the town could rise above controversy and show support for Wilkinson and those who work with her.

In the US as a whole, the situation is not so simple. On Thursday morning, the cardboard sign was gone.