Including Michigan's coasts as "inland water" is like putting a 20 miles zone around Hawai'i. Suddenly it becomes a huge state. Both are examples of offshore water, not internally bounded waters.
I agree. And still, if Canadian provinces and territories were included on this list, Michigan would barely make 5th and Alaska would drop to 8th. Removing the Great Lakes portions (from Ontario as well) would make it that much more stark.