Roy Trakin “What the Hell Happened to Blood Sweat & Tears?” is the question filmmaker John Scheinfeld (“Chasing ‘Trane,” “The U.S. vs. John Lennon”) asked the band’s co-founder and industry acolyte Bobby Colomby over lunch just two months before COVID. The story Colomby told him that day turned into a compelling documentary that serves as the perfect glimpse into the roots of today’s cancel culture in an incident that took place 53 years ago. It was a reasonable query about a band that, as the summer of 1970 approached, was the hottest entity in rock ‘n’ roll, with a self-titled sophomore album for Columbia Records that topped the chart for seven weeks, spawned three massive Top 5 hit singles (covers of Laura Nyro’s “And When I Die” and Brenda Holloway’s “You’ve Made Me So Very Happy” and the novelty-like “Spinning Wheel,” penned by the band’s newly minted vocalist David Clayton-Thomas), while taking home an album of the year Grammy over “Abbey Road,” “Crosby, Stills & Nash” and “Johnny Cash Live at San Quentin.”