Totally avoidable. At least it was the adult owner that was target of the dog instead of a kid or neighbor.
Someone suggested suing. This lady mauling victim won because the landlord never replied to the lawsuit. She may actually see some money.
http://www.animals24-7.org/2018/06/14/4-25-million-award-for-pit-bull-attack-and-the-victim-may-see-some-of-the-money/