Crowd behaviour was poor in those days (and it's not that much better now) - but it was foreseeable. The procedures put into place where designed to take crowd behaviour into account, but having sailed close to the wind previously, on this occasion, it failed with catastrophic consequences.
I don't think anybody can argue that some elements on any crowd act like morons. In a crowd of a few thousand people trying to get into an end of a stadium, there will be some chanting, some trying to climb over a wall and some turning aggressive when they can't get in - perhaps a couple of hundred such people. But there will be thousands more just acting as a herd and trusting that someone somewhere is in control and that eventually, they'll be inside the stadium.
I do understand where you're coming from - because 'crowds' act a certain way and it's not always conducive to safety, but I think the crux of the question is 'did the crowds behave in any unforeseen way that contributed to the danger'.
If someone was killed at a bonfire, nobody would ask 'did the fire contribute to their deaths' - it's more about 'did the control of the fire contribute to their deaths'.
Are crowds dangerous? yes
Are racing care dangerous? yes
But when theirs an accident, you look to see if there was fault in the crown or racing car, and by 'fault' we mean something above and beyond their inherent (known) dangers.