I was watching a comedian joke about how American cops do way too much. Back home, they would tell you to deal with it yourself.
So 19 year old kid, lives at home, mad because mom cut off his cell phone bill because he didn't mow the lawn, mom wants the police .... that's different that a woman calling 911 and saying her abusive ex BF is at her front door, drunk, trying to kick it in. The first case doesn't exactly need police.
The comedian also joked about homeless people. So toothless joe is in walmart's parking lot again, rambling on about how ninjas are after him. That seems more like someone who needs mental help, could use info on where to get it, etc vs a cop pushing him off the property and saying don't come back.
The second scenario doesn't really require a police response either. She simply needs to arm herself and be responsible for her personal safety.
Of course, she can call them after she takes care of business.