I would surmise the use of mountain or montagne is all relative to the surrounding terrain - in many parts of the world Mount Royal (Mont Royal?) would never be considered or called a mountain but for some it is still a mountain. Even the wikipedia article regarding Mount Royal calls it a mountain in it's first sentence as does the city of Montreal's web site (
link.
I've been to and hiked about Mount Royal and by my definition, I would never call it a mountain but then again, the Rocky Mountains lie just over an hours drive west of my home which create a different perspective of what mountains are.
Again, it's all relative and even many organizations that try to define what a mountain is haven't come to some conclusive agreement on that definition. So I will continue to find it amusing and others shouldn't be upset by that - it is what it is.