With that justification, Lucifer should be in Heaven. He was God's creation, he was given free will, and his spirit functioned in a way that was unique to him. So are we God's creations, whom have free will, and have uniquely functioning spirits. The devil didn't like being under God, so he tried to conquer him. He knew what he needed to know, yet thought that he could be outside of God without receiving any bad consequences. It's the same with us...justifying sinful things until God is no longer there...but will we reconsider?