You're saying that it is the evil of mankind that corrupts the true and good, is that right? God's ideas were corrupted by evil men in the Crusades and Inquisition, and the high ideas of socialism were equally corrupted by evil men. In essence, you're saying that both God and socialism exist on a higher plane than their human implementation.
God is indeed higher than man, and his plan goes on despite the meddlings of evil men, because he exists outside of man.
Socialism, on the other hand, is the invention of men...some would say evil men. Regardless, it does not exist outside man, so is entirely dependent upon its implementation by men. As such, it will always be subject to the failings of the men who implement it.