They are banned in Ontario, Canada for a good reason and banned in UK for the same reasons.
The only time my dog was ever randomly attacked was a pitbull and you quickly learn talking to other dog owners how common this is. Nothing clears out a dog park like a pit bull showing up.
I suspect the reasons are (generously) keeping them out of the hands of people who would treat them poorly and perpetuate the stereotypes, or (less generously) ignorance and fear.
The ban isn't meaningfully enforced in much of the province [1], I see them a lot. I used to live in Ottawa, and their official site directly states "The City of Ottawa does not enforce the provincial ban on pit bulls" [2]. For those (legitimately) interested in a Canadian perspective on breed-specific legislation, there's a documentary by CBC's Fifth Estate on the subject [3].
1. https://lfpress.com/news/local-news/five-things-to-know-abou...
2. https://ottawa.ca/en/living-ottawa/animals-and-pets/dogs/dog...
3. https://www.youtube.com/watch?v=iFa8HOdegZA