I don't claim it was created by leftists. Leftists embrace the Cuban flag for the ideology of Castro, but despise the confederate flag because it represents their own failure. All while projecting their own evil upon the conservative rednecks, who embrace it as a sign of their southern heritage.
The only true true difference between these flags, is who they offend.
Can you show me a particular instance, of American leftists using the Cuban flag in support of Castro's, or even general socialist, ideology? I can't recall ever seeing such.