Here is a link to a slightly longer clip with syncronized sound (the video image is horizontally flipped, though.) As for it being longer in length, you will see that it includes dialogue by Sibrel after he's been punched. Rather than Sibrel saying, "Ouch, I'm injured!" or rather than venting frustration at Aldrin, he [Sibrel] asks [the camera person] "did you get that on camera?" If that doesn't say "impure motives" I don't know what does. I don't think Sibrel was hurt, but since it was "caught on tape" Sibrel uses it to his advantage as "proof."

__________________
If only closed minds came with closed mouths!