Yes, Lake Superior is the largest lake by volume in North America. Measuring by surface area of the lake, it is actually the largest in the world. While other lakes are deeper or contain more water, it still places third in volume in the world. Even deeper lakes do not take up as much of what would otherwise be land as Lake Superior does. It is far and away North America's biggest lake by any standard of measurement.
Without more context, I'm not sure how this is a debate. Lake Superior has a surface area of approximately 31,700 square miles. The next closest lakes are Michigan and Huron, which are approximately 22,300 square miles. None of the other "major" lakes even come close to the size of Superior. These are the largest freshwater lakes in North America, and are among the largest in the world.
Yes, it is the largest. A lot of people that live in the Mid-Atlantic and the South often forget about the lakes to the north and how vast they are. Lake Superior draws a lot of visitors each year because of its unique history, geography on the map, and surrounding states.
This is not really a matter of debate, it is supported by the cacts. Lake Superior is larger than all of the other Great Lakes which are the largest lakes in North America. This makes Lake Superior the largest lake in North America, without any doubts or questions because it is measure able.