I take your point but the key issue here is how far a dog of any weight would take its anger and this depends on what its been bred to do, its temperament and upbringing. The Newfoundland, St Bernard and Irish Wolfhound can weigh 70 - 90 kg but all these breeds are famously gentle and placid.
A dog is perfectly capable of inhibiting its bite and can deliver a bite ranging from soft to hard. This, assuming it happens at all, is usually in the form of one bite and release, usually to a hand or limb. Not at all pleasant but usually survivable (other than a baby.)
There are a number of frightening aspects to the XL Bully. Firstly, there appear to be no triggers to its aggression. Secondly, it sees its 'job' as ending the life of the person or dog or cat it's chosen to attack at random (hardly surprising given its descended from the survivors of Pit Bull fights.) Thirdly, It doesn't bite and release, it savages, and it usually goes for the throat. Finally, the XL Bully is unique among dog breeds for frequently attacking and killing its owners (as is it's ancestor the American Pit Bull Terrier.)
Personally, I don't classify the XL Bully as a dog because it typically doesn't behave like a dog. I classify it as a grotesque man-made mutation - the equivalent of a loaded gun - and our government of the day should never have allowed its importation from America.