Hillbilly Heaven, a yet-to-be-opened restaurant in downtown Hamilton that has sparked controversy by showing the Confederate flag on its sign, has been vandalized

On Wednesday morning, the flag above the southern-style barbecue joint, which is set to open on March 11, bore red and black paint splotches. Additionally, the side wall had been spray painted with the word "Antifa zone," a reference to anti-fascism and a response to the restaurant's decision to fly the "stars and bars."

Cameron Bailey, the restaurant's owner, said he noticed the graffiti at around 8:30 a.m. on Wednesday.

"Stupid is as stupid does," he said, reacting to the discovery. "Next time they vandalize it, I'd prefer they make it legible. I don't like it."

Police spokesperson Debbie McGreal-Dinning told CBC Hamilton police are aware of the incident and are currently investigating. She said vandalizing a storefront could result in the perpetrators being charged with mischief.

It's the responsibility of the owner to remove the markings, she noted.

"It's private property, and normally the owner of that property is responsible for taking it down."

The flag continues to be a contentious symbol more than 150 years after it was first flown. During the American Civil War, some army units fighting for the secessionist Confederate States of America carried the flag. Some critics say it represents the painful legacy of slavery and is a direct affront to African Americans and other racial minorities.

The flag is an offensive image, and using it as a marketing tool is "absurd," said Gerald Horne, a professor of history at the University of Houston. Canada has been historically ardently anti-slavery, he said, and nearly became the target of U.S. attacks for it.

"What kind of so-called Canadian patriot will fly the flag of a now-forgotten nation that intended an attack on his homeland?" Horne told CBC Hamilton. "This, to me, is outrageous."

Bailey has said he's "not racist" and charges his critics in Hamilton are unfair to target him and not The Dirty South, a local food truck that is emblazoned with art that resembles the Confederate flag.

The graffiti, as well as the public uproar surrounding his restaurant, "strengthens my resolve" to keep the sign above the door, he added.

"I'm not going to let a bunch of media people, academics or hipsters intimidate me," Bailey said. "If the Supreme Court of Canada tells me to take it down, I'll take it down. But other than that, never."