Good explanation: https://pjmedia.com/trending/another-day-another-apology-for-telling-the-truth/
[African-American pianist Don Shirley (played by Mahershala Ali)]
Hence the existence and spectacular Golden Globes success of Green Book, co-written by Nick Vallelonga, the real-life son of the black piano man’s real-life chauffeur. The other day, Vallelonga, along with Farrelly and Brian Hayes Currie, won a Golden Globe for their script, which under ordinary circumstances would be a good sign that they might end up being nominated for an Oscar. But that hope appeared to be dashed when, only a couple of days after the Globes telecast, somebody unearthed a 2015 tweet by Vallelonga that instantly went viral. In it, he supported a Twitter statement by Donald Trump that thousands of American Muslims had celebrated 9/11. Wrote Vallelonga: “100% correct. Muslims in Jersey City cheering when towers went down. I saw it, as you did, possibly on local CBS news.”
Trump’s statement was indeed true, and not just about 9/11. Muslims have applauded every major terrorist act since. But you’re not supposed to say so. Predictably, Vallelonga’s tweet immediately got him into hot water. One of the companies that produced Green Book, Participant Media, issued a statement calling the tweet “offensive, dangerous, and antithetical to Participant Media’s values.” Dangerous? In reporting on this dustup, the mainstream media were quick to describe Trump’s statement as a “false claim” (The Guardian), as “widely discredited” (BBC), or as “debunked” (Daily Mail).
Unfortunately but inevitably, Vallelonga issued a mea culpa. First he deleted his Twitter account, then he put out a groveling apology: “I want to apologize. I spent my life trying to bring this story of overcoming differences and finding common ground to the screen, and I am incredibly sorry to everyone associated with Green Book. I especially deeply apologize to the brilliant and kind Mahershala Ali, and all members of the Muslim faith, for the hurt I have caused. I am also sorry to my late father who changed so much from Dr Shirley’s friendship and I promise this lesson is not lost on me. Green Book is a story about love, acceptance and overcoming barriers, and I will do better.”
What was Vallelonga saying here? Note what he didn’t say: he didn’t say that, after giving the matter serious consideration and consulting the media archives, he’s decided he was mistaken about having seen Muslims cheering on 9/11. No, the point here is presumably that, even if some Muslims did rejoice in the events of that day, it’s wrong to acknowledge such facts. It’s apparently OK, then, for Muslims to cheer 9/11, but not OK to say that they did.
In addition, one key point was missing from Vallelonga’s apology. Yes, Ali identifies as a Muslim. But he’s an Ahmadi Muslim. "Regular" Muslims don’t consider Ahmadi Muslims to be "real" Muslims. They’re too peaceable. In many Muslim countries, it’s illegal for Ahmadis to identify as Muslims. They are routinely subject to official persecution and mass slaughter in Islamic countries. “Regular” Muslims cheer the murder of Ahmadi Muslims. Last May, a Sunni mob tore down an Ahmadi mosque in Sialkot, Pakistan, and afterwards cheered a local cleric who maintained that he had ransacked it. In 2011, the Sydney Morning Herald reported that “hundreds of onlookers cheer[ed]” the savage slaughter of three Ahmadis by a group of regular Muslims.