The police are not primarily there to solve civil disputes and disagreements. There is a pretty wide area where things are not illegal and possible to convict, but you would probably want to do something.
The police’s mindset (at least the ones I’ve interacted with) is one of three things:
1. Deterrance from crimes to be committed (doesn’t apply here)
2. Achieve convictions for crimes (would also not apply in your situation)
3. Deploy force to break up ongoing altercations (also doesn’t apply)
2 is interesting. Talk about a specific alleged crime with a police officer and they will not be discussing whether it was a crime or not much, nor if the person committed it, they will be discussing whether it can be proven in a court of law or not that a criminal act was committed by a specific person, beyond reasonable doubt. It is a purely pragmatic operation of “how can I provide proof that something occurred that is against this list of rules”.
The police are in no way useless, most people just misunderstand what their job is. Their job is not to dispense justice, or make sure you get your revenge.
In your specific situation it sucked, but from a police point of view what would they do? Is there a crime? Maybe. Would they be able to present a chain of evidence proving beyond reasonable doubt that a crime occurred - most assuredly not. Would a conviction, however unlikely, achieve something meaningful? Nope, the guy would get a fine at most, but would still be working with you.
On the other hand, an employer is fully within their right to fire someone for a situation like that. They do not have the same burden of proof, they can refer to previous records of incidents, and the consequences would better match what you’d want (removal of the hostile environment).