There is so much that could be said in response to your post. Your comment touches on a vast array of theological concepts such as the nature of man, the purpose, extent, and efficacy of the atonement, reprobation, etc. I can’t possibly do these things justice with a quick reply, but I’ve cobbled together a few rambling and disjointed thoughts.
Yes, I believe in the federal headship of Adam. I know men are condemned already because of the sin of Adam. All men inherit the sin nature of our father Adam and stand condemned. The natural man isn’t good, isn’t seeking God, and can’t do right. However, I am in agreement with the Westminster Confession of faith here:
“Every sin, BOTH ORIGINAL AND ACTUAL, being a transgression of the righteous law of God, and contrary thereunto, doth, in its own nature, bring guilt upon the sinner, whereby he is bound over to the wrath of God, and curse of the law, and so made subject to death, with all miseries spiritual, temporal, and eternal.” W.C.F. 6.6 (emphasis added)
Every individual sin binds those who are not made partakers of Christ into an irremediable punishment.
I’ve definitely read past John 3:16 countless times.
“He who believes in Him is not condemned; but he who does not believe is condemned already, because he has not believed in the name of the only begotten Son of God. And this is the condemnation, that the light has come into the world, and men loved darkness rather than light, because their deeds were evil.” John 3:18-19
I believe that this passage shows that unbelief is clearly sin. Yes they are condemned because they do not believe in the name of Jesus, but why do they not believe in the name of Jesus? Because they loved darkness more than light, they loved their own sin more than God. If your view that Jesus paid for the sins of all men is correct, what about the sin of unbelief? Is it not covered by the blood of Jesus as well?
Another thing to consider, hearing the message of salvation is itself of God’s grace. Unknown multitudes live and die having never even heard the name of Jesus, let alone the gospel. Those people still go to Hell, but not because of their unbelief. They certainly don’t go to Hell for rejecting a gospel they never heard. Romans 1 teaches they are without excuse because they reject the light of God they did have. Some argue that God would never send anyone to Hell who never heard the gospel. That idea, were it true, would render evangelism and missions unspeakably cruel. Why should a missionary risk his life to evangelize the cannibal tribes of Papua New Guinea if they aren’t even lost in their sin?
To say that Christ died a vicarious death in the place of all sinners but that not all sinners will be saved is a contradiction. If He paid for all the sins of every single man then every single man will be in heaven. Scripture teaches He died for His sheep and His sheep alone. Jesus didn’t merely make salvation possible, He actually saved a people. If one holds to an unlimited atonement while denying universal salvation, one ends up with a redemption that leaves men not totally free or actually redeemed, a reconciliation that leaves men still estranged from God, a propitiation that leaves men still under the wrath of God, and a substitutionary death that still makes the sinner himself help pay the debt of his sin. All of these aspects of the atoning work of Christ then become nothing more than a possibility that relies upon man to make them a reality. But salvation is of the Lord (Jonah 2:9).
The doctrine of limited atonement affirms that the Bible teaches Christ’s atoning work on the cross was done with a definite purpose in mind—to redeem for God people from every tribe, tongue and nation (Revelation 5:9). Jesus died, according to Matthew 1:21, to “save His people from their sins.” This truth is seen in many passages throughout Scripture. In John 10:15, we see that He lays “down His life for the sheep.” Who are the sheep? They are the people chosen by God from before the foundation of the world (Ephesians 1:4). These are the same ones Jesus said were given to Him by the Father in order that He would fulfill the Father’s will by losing none of them and by raising all of them up in the last day (John 6:37-40). The truth that Jesus came for this specific reason is seen in both the Old and New Testaments. One of the greatest passages on the atonement in the Old Testament is Isaiah 53. In this passage alone, we see that He was “stricken for the transgression of God’s people” (Isaiah 53:8); that He would “justify many” because “He shall bear their iniquities” (Isaiah 53:11); and that He indeed “bore the sin of many” (Isaiah 53:12). These verses and many others talk about an atonement that was specific in whom it covered (God’s people), was substitutionary in nature (He actually bore their sins on the cross), and actually accomplished what God intended it to do (justify many). Clearly, here is a picture of an intentional, definite atonement. Christ died not simply to make justification a possibility but to actually justify those He died for. He died to save them, not to make them savable.
Dr. Clark does a much better and more thorough job with this question than I can.
http://rscottclark.org/2006/08/limited-atonement/
This fallacious position confuses judgment with forgiveness.
The Cross was all Judgment. Forgiveness doesn't occur until the sinner faces God, recognizing through faith in the Judgment of Christ on the Cross, that all sins have been judged, and that by confessing His sins to God through faith in that Judgment, God is now free to forgive the sinner and then give that sinner a regenerated human spirit, thereby providing salvation.
Christ was judged for all personal sins, past, present, and future in all humanity. Forgiveness of the condemned is still required prior to salvation.