Not really commenting on this particular incident, but I was an Animal Control Officer for 2 years in North Las Vegas, dealing almost exclusively with pit bulls. The PD did not provide us with firearms, so we had to use our pepper spray, extendable batons or dog poles to protect ourselves.
I dealt with hundreds of aggressive, viscous animals and was able to protect myself, (please note, not all pits are aggressive/viscous...most would walk up and allow me to put a leash over their head. Just saying I have dealt with hundreds of aggressive canines). I was not bitten by a single dog during my tenure.