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].
Yep, that's why my dog still got attacked by one in Toronto. It's poorly enforced. The dog sprinted across an entire field without making a sound and pinned my dog hard by the throat.
Ontario also tried to remove the pitbull ban, after the usual "it's owners the owners" protests, but a bunch of attacks happened again so they reinstated it.
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