When I face this issue I think sometimes it’s just about semantics. For example, of course only those who are saved, Christ died for, because as He knew all men from eternity. He knew who He was dying for, in terms of actually providing real forgiveness to. However, with the hyper Calvinistic view (which I think you are referring to for Calvin did believe it) I think Calvin was overreacting to the opposite view, Pelagianism. Calvin does not seem to know how to reconcile man’s free choice and God’s desire to save all mankind, with the doctrine of election. This view actually gets itself into theological knots and even some of my favorite theologians have been sucked into it. In the extreme case it is actually proposed that Christ is not even truly offered to all and that He actually does not really love all in the same way that he loved the elect. From this extreme view, God only chooses some and does not choose others. This extreme form of Calvinism is not shared by all Calvinists. I do not think Luther thought this way at all. A window into Luther’s attitude about it all can be found here.
The way out of this quagmire is simple for me. I accept the doctrine of predestination and consider myself a Calvinist. However, where Calvin does not follow the more mature Luther on this subject, I lean to Luther. I do not speculate so much about God’s election of those who will ultimately inherit eternal life, like Luther. Plus, I take the commandment to love our enemies as meaning God must love them also. Luther often seems to be filled with this faith; Luther never clarifies when offering Christ to sinners that ‘Oh by the way this might not be for you.’ Its simple, if God commands us to love His enemies, then He must love them and offer that love through the death of Christ for them. It makes no sense for God to command us to love His enemies if He does not love them. God commands us to love them because He wants us to be like Him. Love must include desiring what is eternally best for them, or else love if hate and hate is love and the Devil could be God and God could be the Devil. The whole thing is nonsense when taken to the extreme through vain speculation. Besides, those who go to hell will go there primary for rejecting His love in Christ. If that love was not offered, then it is no sin to reject it.
The only sure thing we know is:
For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. (NIV John 3:16)
Even if you get into the original Greek and somehow argue that this verse is not applied to all but only the elect (which is what these people actually do) - it makes no difference. God must love the world or He would not ask us to and He does mean the whole world in the verse.