Not a very good idea when you’re already inside grappling range. A handgun becomes useless if a much stronger person seizes the hand that you are using to hold the gun. Additionally, if your first few shots fail to stop him, perhaps he’s on powerful drugs and you have a bad angle, then he can kinda just rip your face off anyway, since he’s already there. Or he could attack with a hidden knife, that’d be unpleasant.
This tells me you have no actual personal firearms training, no one with any training (and sense I suppose) would advocate for threatening an unknown assailant with a point blank gun.
The question becomes, could it reasonably have been perceived as an assailant. And that is a subjective question, a matter of opinion. Answering these questions is the job of juries, and they did so.
Also, I have at no point argued the charges were unreasonable. The charges were reasonable, this was not a clear-cut case. The verdict was also understandable and reasonable, that’s all.
Oh, and if you “fuck around”, you might “find out”. This is an important life lesson in general, that almost everyone learns at some point in their teens to 20s. If they make it that long, without getting shot by a doordash driver for a dumb prank.