If you’re in Canada, that’s highly likely. Why go to the ruinous expense of importing a perishable foodstuff from Italy, and ignore the much cheaper and perfectly good locally-produced alternative? Especially when you’re going to cook it in a commercially-produced convenience food with a lot of other, much more highly-flavoured, ingredients.
It’s also one of the easiest cheese to make at home yourself. I can’t really see any good reason for importing mozzerella when there’s plenty of local cheesemakers who do a good enough job at it. There’s at least one deli I’ve been to in New York which makes its own mozzerella on-site, and it’s great. Fresh white cheese, floating in some brine, just like what you’d get in Italy.