Given rideshare driver (is this relevant?) this smacks of driving while black type discrimination.
I think you're on to something here. Any behaviour becomes 10x more threatening to the public/cops when the person doing it has brown skin.
Obviously the toy looks a bit real, but it seems to me all this needed was “hey we had a complaint, that looked real, why not hand it over and go home for a bit?”
Thing is, he'd already left the scene when he was arrested. They had to track this guy down to arrest him and confiscate his property, and it's not even clear that he was breaking any law. Seems like they would have had time to check that?
I also don't know why they keep saying it was "discharged" like that's a relevant detail. It's not like it made it more threatening, because if you see someone pull a trigger and it doesn't make a loud pop, then you know it's not a real gun (or at very least it's not a loaded gun). Unless this is a weird kind of water pistol that does make some kind of a pop? Also, if people are close enough to see the trigger being pulled then they're probably also close enough to see the spray of water. It'd be far more effective to just brandish it if you wanted to scare people.