Israeli flags and posters of hostages kidnapped by Hamas sparked outrage and a boycott of a Long Island diner, where several staff quit over the show of support and business fell flat — until the Jewish community began to take notice.

Peter Tsadilas, the owner of the Golden Globe Diner in Huntington, said he began displaying Israeli flags and posters as a way to support efforts to return the hostages taken in the Israel-Hamas war.

But many locals have felt differently, according to Tsadilas, who told The Post three staff members quit, several patrons who came in daily haven’t returned, and local DoorDash drivers boycotted the restaurant.

“We’re having kickback from the locals now. We get random phone calls from people telling us that it’s depressing and we should pull it all down, that they don’t want to see this s–t every day,” Tsadilas said Wednesday.

A group of local drivers for DoorDash also allegedly confronted Tsadilas, telling him he was promoting hate.

“The drivers from DoorDash came over and basically said they’re not picking up our orders with these flags outside,” he said, adding that his business soon stopped receiving any type of orders from DoorDash — and that he could no longer find his restaurant on the app.

Tsadilas said his business reappeared on the app after he threatened to take legal action.

In a statement, Doordash denied that there were any issues at the diner with deliveries or drivers.

“Based on our investigation so far, we have not found any evidence to confirm any of the claims made by the diner owner,” a spokesperson told The Post.

A week after the alleged confrontation, Tsadilas noticed things starting to take a turn after a customer, who said she was Kosher, came in because she saw the posters and began telling her friends to come to support the business.

“After that, she sent an email and it went viral,” he said. “They’ve shown us tremendous support.”

Posts shared online of the small, coffee shop have spurred patrons to trek out to eat at the mom-and-pop shop from as far as Philadelphia, New Jersey and Delaware — and business has been booming ever since.

Tasadilas, who is Greek, admitted there were moments at first when he second-guessed the eye-catching arrangement.

Now, however, he plans to hang up even more posters of hostages alongside a homemade sign reading “Greek Diners Stand With Israel.”

“I’m not Jewish, but my father-in-law is Jewish. My partner is Jewish. My best friend is Jewish,” he said. “You know, it’s the humane thing to do. And, we want to find these people and bring them back. It’s not my family, but if it were, I would want people to speak up about it.”

Long Islanders have been stopping on Main Street, double parking their cars, and getting out to take pictures of the restaurant, Tasadilas said.

The diner owner says he looks at the images of kidnapped three-year-olds and mothers and imagines it’s his own daughter or mother.

“It becomes real. Now I feel real pain of what the people feel with their families missing, not knowing where they are, what they are doing, and whether they’re being treated well. Whether they’re alive or dead. And it’s not fair,” Tasadilas said.

While the initial backlash was a heavy blow, Tasadilas says he appreciates being backed for doing what he feels is right.

“We’re all people. I don’t want Palestinians to die. I don’t want anyone to die. But what happened to Israel was an attack,” he said. “These are people’s kids, and fathers and mothers. It’s disgusting. Wars should be left to countries and armies, not innocent people.”