Mags cares so much, and also she wants to do a murder whenever anyone harms her people.

I'm never quite sure whether canon is hyperbolic when it says Maggie has 2 dozen dogs, because it's written from Shaun's point of view and he's not a dog person. But she might literally have two dozen dogs. A ridiculous pack of overbred purebreds abandoned due to health problems; I headcanon that the primary thing she uses her trust fund for is the astronomical vet bills.