FWIW, I have spoken to someone who was present when the group KB was with saw the large male. That person was standing right there in nearly the same spot and said he/she saw nothing.
I have a heck of a lot of respect for KB. I do NOT believe he is lying, hoaxing about anything he claims. However, I do feel like the power of suggestion could be at play. No disrespect intended to those that believe they saw something that day. I really feel like they all believe what they say they saw. But belief is belief. It's not reliable, it's not scientifically accurate, and it's flawed with perception, bias, and many other things that can influence it.