First Nephi 7:14

For behold, the Spirit of the Lord ceaseth soon to strive with them; for behold, they have rejected the prophets, and Jeremiah have they cast into prison. And they have sought to take away the life of my father, insomuch that they have driven him out of the land.

God has great patience, but he is able to judge when men are hardened beyond reach. He expelled Lucifer when he knew he could not be turned.  Men can likewise become so determined to choose evil that their time of probation is wasted. Rather than let such evil corrupt the next generation, he may destroy those who harden themselves against him. He does not hate them, he loves them. If they will not repent in mortality, perhaps they will change their minds on the other side of the veil. Hope is not lost until the final judgment at the last day. Hardening of the arteries is a disease; hardening of the heart is a choice.