I think the point is that he wasn’t an amateur and the guy was. He was trying to do a job and they got in his way.
Replace batman with a firefighter and give the guy a water pistol and it’s the same story.
I mean it’s not like you can major in Batman studies or go down to the Batman Trade School and become a professional Batman.
Batman is just as much an amateur as that guy is, he just has more expensive gear.