Honestly...yeah, domestic disturbance call, there probably wasn't (or it would have been recorded as something else). But we also don't know what the 911 call said. If someone says they hear crashing noises, breaking furniture and loud screaming, you have to assume the worst. At least, I sure as hell hope the cops would.
Why the hell would you hope a cop "assumes the worst"? Do you even realize what that entails?
A cop assuming the worst means that cop engages in
riskier behavior because he
believes it's necessary. Assuming the worst means tear gassing a crowd because one of them
might have a gun. Assuming the worst means busting down a door with a weapon drawn because the person who called in the report
might be in trouble. Assuming the worst is why innocent people and children have been shot and killed by mistake in botched raids, people injured with 3rd-degree burns with flashbangs, etc., because the police involved are executing measures
reserved for situations that
are the worst. Police engaging in more drastic measures than they should just because the situation might possibly be worse than expected is how some very bad things happen. The police should be capable of dealing with the situation going sour, yes, but there is a limit, and it shouldn't mean doing things that endanger other people's lives or make lethal mistakes far more likely.
I guess we disagree on how much 'clear evidence' is needed here, but depending on what the caller said, I'm willing to give them an awful lot of leeway. Specifically, I'm willing to give the cops exactly as much leeway for "He's beating her and she's screaming at the top of her lungs" as I am for "There's someone in my house and I don't know who it is" in a bad neighborhood, and I'd hope they respond to the latter with gun drawn.
Even if there's good reason to believe someone might be violently beating another person, if there's absolutely no reason to believe the perpetrator is actually armed with a firearm, there's little reason to bust in the house with it drawn, at least not to the point where you can't react to any quasi-plausible danger except by shooting at it. If having a gun drawn actually prevents you from using pepper spray or a nightstick or any other means of disabling a person (or in this case, some dude's dog), then you better make damn sure the gun is
necessary first.