Yeah, that part and Malcolm cursing struck me as false. Also, for the most part I liked his back and forth with Sam Cooke but thought he went a little TOO hard at points. It worked for the movie but I doubt the real Malcolm was that harsh toward Sam
We aren't sure how the relationships of Malcolm and Sam was in real life, but based on their personalities that we do know of, a clash of views is possible. Even close to crossing the lines. There's been plenty of audio debates where Malcolm was outright cruel towards other black commentators and that's just on a public venue. Who knows how he was in private. Another thing to keep in mind that people KEEP forgetting, just because he's Malcolm on the outside, he still had a little bit of DETROIT RED in him. So, a depiction of someone who's already stressed, uncertain about his future because he was on the verge of leaving the NOI, on top of disillusioned over the truth of his mentor and leader who molded and changed him into that Malcolm X that we all know, taking out his emotions at Sam Cooke who was just egging him on the entire time isn't much of an impossibility. Malcolm was still human.