Has an Olympic Hockey (Men) game ever ended 21-1?
Exactly once. On February 3, 1948, Canada beat Italy 21-1, and no Olympic Hockey (Men) game before or since has ended that way. When it happened it was a scorigami, the first 21-1 in league history.
That makes 21-1 the 75th most common final score out of 99 that have ever occurred in Olympic Hockey (Men). One point away, 22-1 has happened never and 21-2 has happened never.