"Introduced" is a subjective word. The Alto had a mouse, but I don't think it was used outside PARC. It doesn't seem too far from the truth to say that the Macintosh introduced the mouse to the world.

The Apple Lisa had a mouse so if we are looking for inaccuracies that is a better argument to start with..

It was the first PC that was widely available, that shipped with a mouse. There were mice before that of course. But the Macintosh was centered around the use of the mouse.