Many Christians oppose the doctrine of predestination on different grounds
One ground Christians reject the doctrine of predestination on: The Doctrine makes God unjust
Calvin's response was that humans cannot presume to understand God's will, and in any case the evil actions of the damned show that God's decision was just.
Another ground Christians reject the doctrine of predestination on: it cannot be reconciled with Jesus' portrayal of God as unconditionally merciful, forgiving and loving
The Calvinist response would be that no one merits salvation, so God's saving anyone at all is a display of his mercy, forgiveness and love.
Another ground Christians reject the doctrine of predestination on: it cannot be reconciled with the concept of free will, as if God foreknows our actions, then we have no choice but to obey or disobey his will.
One response to this is to point out the God's omniscience is not causative