My brother lives in Lachine, and the banning of pit bulls came about by the mayor being treed by two of them, owned no doubt by the kind of scum who is hurting all of us.
BSL is nowhere near the magnitude here that it is in the US, partly because the population is so much smaller, other than in major urban areas, particularly the Toronto - Hamilton area, where there is a big dogfighting problem.
I've never seen a pit bull in a shelter here, and in fact had to travel 600 miles to get mine! Of course, our shelter kills nearly everything that comes through the doors, so that could be it too.
That's not to say there are none in downtown Montreal, or that there is no problem,(I'm sure there is) but I have never heard it.