Calvinist Greg Welty states: Clearly then, the controversy between Calvinists and non-Calvinists over unconditional election is not the Calvinists’ assertion that God elects some for salvation, since non-Calvinists believe this too. Rather, the controversy is over the Calvinists’ negative claim, namely, the denial that divine election unto salvation is on the basis of works or foreseen faith. (link)

That the doctrine of election (or, as some would have it, predestination) is taught in Scripture is rarely denied. There are those who teach that election or predestination is only related to salvation via means of Christian service. For example, Jack Cottrell writes:

Among those predestined to fill specific roles in the accomplishment of redemption, the primary character is the Redeemer himself, Jesus of Nazareth. The election of Jesus is the central and primary act of predestination. . . . At times other individuals were chosen for special roles in order to facilitate God's purposes. . . . As instruments for establishing the church another group of individuals were chosen, namely, the apostles. . . . That such election was for service and not salvation is seen from the fact that even Judas is among the chosen twelve (Luke 6:13; John 6:70), though his predetermined role was that of the betrayer of Jesus (John 6:71).¹

Corporate election is the idea that election is primarily about a group and secondarily about individuals. It’s most clearly seen in the OT concept of Israel and the NT concept of the church. Philip Limborch addressed the objection that corporate election rules out individual election:

In the first place it is objected that the predestination we have defined, is not that of persons, but of faith; since faith is thereby predestined as a condition of salvation. Answer. He who elected faith as a condition to be performed by men if they would attain eternal life, has truly elected men under that condition, and in His decree has an immediate regard to people. Therefore these two things, viz., the person and his qualification, are never to be separated, but are always to be joined together. (Philip Limborch, A Complete System or Body of Divinity, both Practical and Speculative. P 344-345)

Scripture paints a manifold view of election:

The sovereign God “decides who will believe and undeservingly be saved and who will rebel and deservingly perish.”

—John Piper, “How God Makes Known the Riches of His Glory to the Vessels of Mercy,” sermon on Rom 9:19–23 (February 16, 2003). [Quote taken from http://andynaselli.com/framing-the-doctrine-of-election ]

Did you catch that Piper claims that God decides who will rebel? And then, those who rebel because God decided they would, somehow deserve to perish for that God-caused rebellion? And this does not make God the author of sin?

We know that many Calvinists believe such unbiblical and seemingly heinous things. But thankfully, it remains shocking to hear them state it so plainly. Otherwise, perhaps we should Recover a Sense of Incredulity over Calvinism as Jim Leonard has suggested here.