Domestic disputes are probably one of the top reasons police are called. Cops hate those calls because they never know what they'll find. Domestic disputes can turn deadly. To dismiss domestic disputes as not being important enough to call 911 makes me think you may not have much experience with domestic disputes, which of course is a good thing.
My full statement was "unless you want to invite a SWAT team into your house, you should not call 911 for a domestic dispute."
I do not believe this idiocy falls into that category.
Furthermore, as you said, cops hate domestic disturbance calls because they never know what they are going to encounter and are primed to respond to violence with violence.
The point the dispatcher was making was that, by requesting police assistance, she was defining this to be a situation in which somebody might get shot.