The Bullmastiff is a devoted, alert guard dog, with a good-natured temperament. Docile and affectionate, but fearless if provoked. Although unlikely to attack, it will catch an intruder, knock him down and hold him. At the same time, it is tolerant of children. Intelligent, even-tempered, calm and loyal, these dogs crave human leadership. The Bullmastiff is extremely powerful and needs a firm master who is confident and consistent with the rules set upon the dog.
Uh, no. Sometimes you just have to accept that there are messed up individual dogs, just like people. What we don't know is what the owner has done to this animal or the breeder to its line. Bottom line a child has died because of it. Prayers for his soul and his family.
Whether you like it or not, there are lists of dangerous dogs out there, all I said is I think I have seen Bull Mastiffs listed. I respect your right to disagree with those lists.
http://www.ukandspain.com/dangerous-dogs/