Dumb doesn't mean it's untrue.
Then why is it dumb if it's a true statement? As the facts (see above posts) clearly support the OP, which make his statement true, isn't it your statement calling the OP "dumb" actually the "dumb" statement? Isn't calling someone's statement "inconvenient" because he didn't google it for your benefit as "dumb" as you conveniently not googling to support your statement?
Bottom line: the statement re: defenses win championships is supported by the facts. Your statement calling it "dumb" is not.