You are confusing what Satan said with what God did. God placed a curse on (1) the Serpent, (2) the woman, (3) the man, and (4) creation.I think you need to write your own bible; it is God who says man became like God after knowing good and evil.
God knows the DIFFERENCE between good and evil, but God is Light, and in Him is no darkness at all.Does God know good and evil?
On the other hand, for humans, knowing good and evil resulted in doing more evil than good. That's why they became like the devil.