Its an information/risk asymmetry problem too right.
For an individual its better to be safe than sorry on something like a stalking incident.
For the cops dealing with a plethora of complaints, on average, most of these resolve to nothing..
Further, these complaints often come with unspecific information thus requiring some amount of surveillance, some of which is easier for the victim to do (put cameras up your own property) than they are able to do legally, especially without a warrant.
Further, with some information in-hand from surveillance, the victim also has access to all their own social media/etc accounts that you can try and make connections between whatever information you collect.
Most people are probably not going to be be OK with "sure we can help you, but we need to put cameras on your property, car and permission to login to all your social media accounts / email / texts, is that ok?"
Obviously this is not ideal, but the vast majority of cops are not detectives. They aren't sending out their best to every seemingly minor call.
I had a friend involved in a domestic incident and when the cops showed up, because she had fought back enough, they both showed evidence of a struggle, and the guy lied about incident. So the cops spent less than an hour on site, shrugged their shoulders and dragged them both off to lockup to go sort it out with a judge in the morning.
One alternative is maybe she didn't fight back and the cops would have seen only marks on her neck and took only him away, maybe. The other alternative is, she didn't fight back, and he choked her to death.
It's often better to fight back than to let yourself get killed while waiting for law enforcement, but there's also a risk that whatever contact with law enforcement you make will not go precisely your way, immediately, without side effects.