Yes, that dog needs to be put down. Even if the Mexican rat had it coming.
As for the whole breed? Nah.
Very few +35 lb dogs lead lives anywhere near the lives they were specifically bred to live.
And pitbulls are hardly the only dogs bred to be spirited & aggressive. As one of the more trainable, feisty & athletic breeds out there, they will continued to be valued. In the right hands, they make very fun dogs to be around.