Why has a crucial scene been edited out?

I first saw this film as a child about 1956. The scene that really stuck in my mind was when Richard's and Henry's foot soldiers are engaged at Bosworth field and they drop weapons and embrace with Richard's soldiers going over to Henry's banner. Since that first viewing I must have seen the film thirty times- including in a movie house that shows vintage films - and the scene is always missing, until I recently saw it on a TCM showing. Granted, I guess if you are going to edit you don't want to remove any of Shakespeare's dialogue but battle never made sense when it was removed. One scene shows Richard's foot going confidently into battle, and soon after he is making a kamikaze charge with a small group of knights trying to kill Henry. Why did he do this? What happened to his army? While historicaly I haven't read anywhere that at the real battle - which by the way was one of the poorest documented battles of that era-
that Richard's soldiers defected en masse, it does seem that many commanded by the Duke of Norfolk deserted, and thus was a motivation for Richard to try to take matters into his own hands, so their is a kernal of truth in the picture's potryal. The question of why this edit was done in the first place and why it has in fact become the standard version of this film is a huge one for me.