People seem to be confusing de facto negligence with criminal or culpable negligence. Dropping a gun, and trying to catch said gun, is negligent in a sense. But how do you establish mens rea with regard to a poor reflex action?
Culpable negligence usually requires either utter recklessness, or else deliberate undertaking of actions that a reasonable person should know would be likely to result in harm.
A fair number of people, just based on numbers who post here, seem to think Mexican carry, and unholstered pocket carry, are just fine. It could be argued that a reasonable person might not see an obvious likelihood of harm from such practice. (IIRC, kraigwy pockets a snubby without a holster.)
So, unless Wisconsin mandates the use of holsters (as some states do) or safeties (also as some states do), then this guy may be a knucklehead, but that does not make him a criminal.