She's also clearly admitted to not training the dog to let go on command.

Fair but forgivable; nobody knows if they'll need that kind of training for their dog until it happens, and training is expensive. Dogs have a spectrum of temperaments, and OP implies that this is the first time an actual attack has happened. No mention of bites makes me believe that there were no biting incidents; I'm certainly not going to assume otherwise when all I have to go off of is "he's protective and not trained." It's unfortunate that she learned the need this way; it would've been preferable if the dog had not mauled someone (should go without saying, but you're not exactly being rational, so I'll throw this in for good measure).

Peoples right to own dogs is not people's right to let their dogs free roam UNTILL an incident

This is a dog in a house. This dog lives there. The dog is roaming in its own space. This point doesn't apply here.

She said the dog is sometimes aggressive and protective.

To what extent? Mauling people, or barking and growling at people? You don't know which one, so that's a moot point.