I haven't seen it yet but I've got it on the DVR. I can understand Frazier's hard feelings, especially since Ali is pretty much a deity now. Frazier was a great, great heavyweight and insanely tough. It's amazing that he has what appears to be all of his faculties given that you couldn't sneak a punch past his face.
I read somewhere a while back that sometimes he would scribble over Ali's name when he was presented items to sign that already had Ali on them.