Come on, those early 1960s hearings were big time. Not as big as the initial Mafia hearing ten years earlier, but with the Mafia fresh in everyone's mind now, you had the Team Sports hearings a couple years earlier, Marciano testifying, Dempsey, Louis, LaMotta admitting the fixed fight, Tunney, etc. everybody's living room learned all the sorted details. I read somewhere one time, the ratings for those hearings was a big as any boxing match on TV at the time.
The fact that the IBC who ran promotions at the Garden, Yankee Stadium, Polo Grounds, etc was controlled by the mafia became front page news.
Everyone knew way before Don King ever convinced Ali to show up at a Cleveland Hospital for charity.