Received I fail to see how the same arguments are not equally applied to synergism/Arminianism.
Both Calvinism and Arminianism affirm that all men are fallen and cannot help but be sinners, due to being unregenerate and being part of Adam's posterity.
This is not unique to Calvinism.
Both Calvinism and Arminianism affirm that if men were left to themselves, all men would perish to hell. Thus both Calvinism and Arminianism affirm that God must give some kind of "enabling" grace to allow men to accept the gospel.
This is not unique to Calvinism.
The difference between Calvinism and Arminianism is not that an "enabling" grace is given, but rather, the difference is merely what that grace actually accomplishes. In Arminianism it accomplishes salvation some of the time, in Calvinism it accomplishes salvation 100% of the time. (I fail to see how Arminianism's grace is better or more gracious, but I digress)
Both Calvinism and Arminianism affirm that God chose certain sinners to be saved before the world was created. (Both must affirm this because it's what scripture says - Ephesians 1).
God choosing certain sinners to be saved before they are ever born is not unique to Calvinism.
The difference between Calvininism and Arminianism at this point is not when God chose sinners to be said (as said above, both affirm it was before they were even born), but rather, the difference is merely why God chose some sinners and not others.
If you really want to "attack" Calvinism, you should attack it at these points of difference, and find out what the Bible says about those particular things. Instead, (as this thread shows in your opening argument), you are attacking Calvinism in a place where it is no different than Arminianism, thus, you are in essence unwittingly attacking Arminianism as well, which I presume is your own position since you are not a Calvinist.
ps. by the word Arminianism I am referring to all forms of synergism, save pelagianism
If you really want to have a discussion where people can learn from each other, why not think through your arguments a bit better? Let's talk about the differences between C and A, not their similarities.
Why is regeneration mandatory in Calvinism? Why does prevenient grace not work/ie is not sufficient in Calvinism? Does Calvinism have a certain view of fallen man's ability (or lack thereof) that requires it to hold to a more efficacious form of grace?
If we ask these kinds of questions, real discussion can take place and we can all learn something about what the Bible says about our sinful, helpless state and what exactly God has done to graciously save us.