Lucifer had a free will and he chose to sin against God, just as all the others with a free will do. The only free thing they have is the choice to reject God's grace, but apart from that they are in bondage to their sin, and God has chosen to leave them in it.
God didn't have to save any of us, we all deserved judgement and hell. The fact that He chose to save some, shows that he is a loving and forgiving God who demonstrates His mercy by saving His elect.