God created man with the ability to sin. Adam chose to sin. Because of that, all men are sinners. God didn't make man sin, but He allowed him to sin. One must conclude that since God allows sin, it must serve a purpose, else He would either have not allowed it in the first place, or He could have just judged Adam and Eve, not allowed them to reproduce, and ended it that way.
We must remember also that sin did not originate with Adam, it originated with Lucifer. Obviously it serves a better, higher purpose for sin to exist for now, although it will be done away with finally at the End of the Age. But sin is not chargeable to God, because He didn't commit it, nor is He responsible for those who bear its curse. That leaves Him free to show Mercy on whom He will, and to harden whom He will. He causes that which opposes Him to bring about His Purpose, something which we are not privy to, except for what he has chosen to reveal to us.
No man is judged for the circumstances of his birth. He is judged for the sins he commits in violation of the knowledge of God which he has. But his sinful nature ensures that he will reject that knowledge, and seal his fate. That sinful nature was inherited from Adam, not decreed upon the individual.
Wasn't it CTD that was arguing a while ago that there were several members of the Swarm that were of the belief that God was the author of all things, even sin? And wasn't that how he (and others) have defined hyper-Calvinism?
HyperCalvinism is the belief that evangelism is unnecessary, because God has decreed who will be saved, apart from any agency to bring about their salvation. ctd is trying to establish that a belief in Predestination and Election, as Calvin and Dordt defined it, are defacto HyperCalvinism. In other words, he is trying to state that mainstream Calvinism is hyper, something akin to saying that the political spectrum runs from Totalitarianism on the far left to Facism on the far right, when in reality that spectrum is entirely leftist, because the true spectrum is Totalitarianism on the Far Left to Total Anarchy on the Far Right. ctd starts from a faulty premise, and his conclusions are not supportable or accurate.
Your conclusion is wrong. The only proper conclusion is that God allows sin, but the sins of men cannot alter God's ultimate plan for mankind. About the only sins that served a purpose were those related to the birth, life, death, and resurrection of Jesus Christ as prophesied.
Here's where we run into problems. You say that God created man with the ability to sin (in laymen's terms, the much-maligned "free will"), and that God didn't make Adam sin but allowed it. But there is a difference between "allowing" sin to enter the world, and setting it up as part of the so-called Eternal Decrees. For God to positively decree all things that come to pass is not the same thing as God permitting it; it is the difference between contingency and necessity. If sin is contingent, it means that God permitted it contingent upon Adam's perfectly-foreknown actions. But if it is necessary, then it means that God has made it that there is no other way that it could be except for Adam to sin: God actively decreed it.
You said, on the one hand, that God positively decrees all things, which would include sin. But in this post, you say that God "allowed" sin. Which is it? If you say that God "allowed" sin, then you agree with the Arminian in saying that sin is not a part of God's actively-decreed plan. But if you say that God decreed sin, then you agree with the blasphemer that God is the direct author of sin, because "all things come about because of his decree."
But sin is not chargeable to God, because He didn't commit it, nor is He responsible for those who bear its curse.
For sin to not be chargeable to God, God could not actively decree that sin would occur, which would mean that Boettner was wrong.
That sinful nature was inherited from Adam, not decreed upon the individual.
So was Adam's damnation blameable on God, then? Because according to some strains of Calvinism, God actively decreed that Adam would sin.