Calvin... Pelagian. Oh my.
I can somewhat see what he means. Both deny God's agency and discretion.
How does Calvinism deny God's agency? The entire theology could be summarized in Psalm 115:3; "Our God is in the heavens, he does whatever he pleases."
It sees God as implacable and unchanging. Indeed, the whole rotten doctrine of predestination, at least as far as Calvinists typically present it, is based on everything being already predetermined, nevermind that it means that God must have planned Adam's fall.
Again, I'm a bit confused on this criticism. Rome (and I believe Wittenberg and Constantinople) teach that God is unchanging just like Geneva, so I'm not sure why we're getting put in the same box with Pelagianism.