Interestingly he did not actually deny the claims when he punched that guy. Just resorted to violence. Maybe he hit a nerve?
No, he didn't "just resort" to violence. Most people haven't seen the full video. Sibrel lured Aldrin to an interview under false pretenses. When Aldrin realized what was going on, he ended the interview and attempted to get up and leave. Sibrel tried to head him off, but Aldrin pushed his way past. When Sibrel prevented him from getting to his car, Aldrin then returned to the hotel lobby where the hotel staff tried to keep Sibrel from cornering Aldrin. Again, Aldrin tried to get out and to his car, but again Sibrel pushed him into a corner of the patio and poked him with the Bible, calling Aldrin names such as "You're a liar and a thief." Only
then, physically cornered and threatened, did Aldrin punch Sibrel.
Most of the Apollo astronauts have prior experience with Bart Sibrel, as he has been stalking them for years. Are you really seriously trying to tell us that a man who has, for 40 years, steadfastly claimed to have walked on the Moon following an exemplary military and academic career, and has plenty of evidence to prove it, has any obligation to make a special effort to deny, in that moment, the baseless claims of a physically belligerent guy who makes his living harassing him and his colleagues? You're seriously telling us that Aldrin's credibility versus Sibrel's is defined in that precise moment?
Get real.