[evgen]

> it's disconcerting that places like Canada and the UK allow people to own such creatures

Just for reference, the 1991 Dangerous Dogs Act in the UK imposes strict liability (including criminal liability) for dangerous dogs and maintains a list of breeds that are banned. Recently 'XL Bully' dogs were put on that list, but there is controversy regarding the breed-specific limits. It is always easy to look back and say 'that dog and its owner were the source of a series of problems and should have been detained' but turns out that preventing future problems is harder than you would think...