Pink Floyd front man and notorious anti-Israel activist Roger Waters published an open letter slamming a Jewish businessman for pulling financial support from a Canadian university over a mural that has sparked controversy for depicting what critics see as anti-Semitic imagery.

The mural, which hangs in the student center of Toronto’s York University, depicts a Palestinian holding rocks as he faces a bulldozer. In late January, Paul Bronfman, a Jewish backer of the university, demanded that the image be taken down, calling it “pure hate” and threatening to pull his donations to the university if it wasn’t removed.

Waters’ letter, which is addressed directly to Bronfman, accuses the businessman of using “economic muscle” to forcibly remove the painting, called “Palestinian roots.”

In his letter, Waters contends that protesting Israeli policy is not anti-Semitic, and is in fact “a moral duty.”

According to Waters, the Palestinian depicted in the artwork, which he insists is not a terrorist, “has a legal and moral right, under the terms of Article 4 of the Geneva Convention to resist the occupation of his homeland.”

Avi Benolo, director of the non-profit Friends of the Simon Wiesenthal Centre in Toronto, called the painting “a call to murder,” and said “the Jewish community will continue to call for inclusion and for freedom from victimization, marginalization and Anti-Semitism.”

York University President Mamdouh Shoukri issued a statement saying that while it is clear that the subject of the artwork is offensive to some individuals and groups, the Student Center where the painting hangs is a separate entity from the rest of the university.