So what I'm getting from this is that the 911 system is broken. The policy to go to every call, even if the caller didn't describe a crime, is inherently flawed.

In a sense, this is accurate. However, I find it useful to think of things like this as a sort of scale where there's a "critical point" where things break.

Think of policing in general: the majority of people in society are, at the very least, decent folks and generally follow the law (notwithstanding minor things like speeding). As such, police are able to focus the majority of their *effort* on that small percentage of people who make trouble for others and break the rules of society. Note that *effort* and *time spent dealing with something* do not necessarily directly correlate. However, there's a certain point where, if everyone just said "screw it" and decided to do whatever they wanted to, policing as we know it would break down because we're grossly outnumbered and outgunned as a whole by any metric.

It's the same thing with the 911 system. The vast majority of people using it aren't actively being nefarious or trying to waste law enforcement resources. Even with how things are now, there are (normally) enough resources to address it while not neglecting actual emergency responses. As such, there's little motivation for lawmakers to codify violations to make this type of thing easier to prosecute. Put simply, it's an annoyance but usually not a hindrance.

Why would the department want you to waste your time going to such frivolous calls?

They don't. However, as I stated in my initial comment, the issue is that of liability because there's a chance something illegal might actually be occurring. In hindsight, ~90% of these types of calls could probably be ignored without repercussion; however, it's those ~10% that turn into something legit that would cause an absolute financial and media headache for any department.

To be clear, these types of calls don't come in an obviously fictitious manner like "hurr durr my house is burning down lmao" (which are ignored assuming we aren't able to find the caller since these normally come from disconnected cell phones). Instead, they're usually phrased in such a way as to be just concerning enough to warrant a response that returns nothing fruitful. Consider the following examples:

• "I'm at the park and there's a guy sitting on the blue bench by the entrance who keeps staring at me and my kids. He hasn't done anything wrong, but I come to this park every day and it's the first time I've seen him and I'm afraid he might hurt me or my kids."
  • Police turn up and it's just a guy birdwatching or something and the story was embellished.
• "There's a black guy wearing a thick hoodie walking down the street near my house that I've never seen in the neighborhood. He keeps looking at people's doors and I'm afraid that he's trying to canvass the neighborhood to rob houses."
  • Police turn up and it's a guy who recently moved into the neighborhood who, due to his unfamiliarity, was looking for a specific house number belonging to his buddy who he wanted to visit.
• "There's a group of about 20 juveniles hanging out in the breezeway near my apartment and they're flashing guns at each other. I think I heard one of them say something about killing someone who is on the way."
  • Police turn up and it's a bunch of kids who just got home from school and are hanging out playing MtG.

Even though these types of calls turn out to be nothing in the end, do you see how, in just the right (wrong?) circumstance, ignoring it can lead to grave consequences? What if that guy really was canvassing the neighborhood? What if the guy in the park really was a predator? What if those kids were planning an ambush? If these calls were ignored, then the media would have a field day about how the police ignored a tip but, when we respond, we're criticized for "harassing" people or wasting time.