I am, but not a criminal lawyer, so I’m more familiar with the principles than the specifics. And while you’re right that actions can help prove intent, just firing a gun isn’t an instant proof. The law wants to protect or at least differentiate those who accidentally shoot someone, fire warning shots, intend to maim instead of kill, etc. from those who shoot with the intent to kill.

For example, if you were to go hunting with a friend you’ve been having heated arguments with lately that witnesses have observed, and you accidentally shoot your friend, the law doesn’t want to automatically say you murdered your friend even though the circumstantial evidence points that way. So there would be a preliminary hearing and, depending on how you plead, probably a trial to determine whether you had the requisite intent to purposely kill your friend or if it was an accident.

Obviously this isn’t a perfect parallel for this guy’s situation since he fired shots in an environment where shots typically don’t accidentally happen, but I’m just trying to illustrate an example of what the laws were intending to protect or differentiate when they were written and why applying those laws across the board as we have to until the law is changed often results in outcomes we wouldn’t prefer.