> dog playing with some rope toys, brought it to us sitting, this guy picked up

Probably a case of ressource guarding.

Many dogs are dangerous not because they are trained to but because people don't train them at all beside to sit and to lay down.

Dogs are certainly not psychopathe that attack out of the blue, they have motivations and reasonings. Most often a lack of education and socializing.

When I see people puting their dog in a cage at night and then puting them on a leash to walk it a few times per week, yeah, that's ticking bombs.