I thought the 'moron contained a contradiction, like cheerful pessimism (or so google tells me) whereas a tautology means redundancy.
I am no the grammar police, but as Dave Barry said, "I could easily overemphasize the importance of good grammar. For example, I could say: "Bad grammar is the leading cause of slow, painful death in North America," or "Without good grammar, the United States would have lost World War II."
Word can KILL.