If all the police did was investigate, then their conduct would have been fine. But they arrested him, and that is not adequate conduct.
On the other hand, the neighbour had made at least 4 reports to the police about harassment and death threats. I believe the neighbour's brother and parents had also spoken to the police in support of these claims. On the day of the arrest, the neighbour had _just_ made the most serious claim yet--about death threats.
Given that context, I can understand why the police legally have the right to arrest, and would be willing to arrest.
Maybe the police should have investigated it earlier, but lack of that earlier investigation is not cause for arresting him.
We should actually be completely fucking outraged that any citizen can be forcibly detained on the whim of the police for non-violent behavior. Yet you seem to think it's just fine to deny a person every basic human right on the whim of some cop?
It took years of complaints and police calls, for the guy to get a court date (For harassing the neighbors and vandalizing their cars.)
Unless you actually go through many of the steps of investigating, you have no idea if the person making the complaints is the anti-social shithead, or if the person being complained about is. '4 official calls = complainer is full of shit' is a terrible heuristic.
[1] Who I trust and respect very much. I doubt that he's full of crap.
[2] Who, from all accounts, wouldn't benefit from a fine or prison sentence - he needs therapy.
I'm not saying this is the case here, but here's a hilariously well documented instance: https://ymeskhout.substack.com/p/sorry-for-arresting-you
Yes, yes I know "just following orders" shouldn't be an excuse.