One of my Top Ten Reasons for rejecting Christianity is that Jesus taught the doctrine of Hell. Before I get into the details of this objection, let me give a general overview of the problems.
Moral Objections to Hell
Jesus taught that some people will experience eternal torment as a punishment from God. This belief in Hell implies that God is cruel and unjust. But God is by definition a perfectly good person, so God cannot be either cruel or unjust. Therefore, by teaching the doctrine of Hell, Jesus has falsely characterized God as being cruel or unjust. But if Jesus has falsely characterized God as being cruel or unjust, then clearly Jesus is not the divine Son of God, and Christianity should be rejected.
Biblical Objections to Hell
Furthermore, the Bible teaches that Jehovah is a merciful and loving person who views humans as loving parents view their children. If the Bible is correct in this characterization of Jehovah, then the doctrine of Hell is false. So, if the Bible correctly characterizes Jehovah as a merciful and loving person who views humans as loving parents view their children, then Jehovah would not punish any human with eternal torment. Thus, either the Bible is seriously in error about the character of Jehovah, or else Jesus is mistaken in teaching that Jehovah will inflict eternal torment on some humans. If the Bible is seriously in error about the character of Jehovah, then Chrisianity should be rejected. If Jesus is mistaken in teaching that Jehovah will inflict eternal torment on some humans, then Christianity should be rejected. Therefore, Christianity should be rejected.
Historical-Cultural Objections to Hell
Finally, the doctrine of Hell is not taught in the Old Testament, but instead arose in the time between the Old and New Testaments, prior to the ministry of Jesus. Since the doctrine of Hell is not taught in the Old Testament, and since we can account for the origin of this idea naturally, apart from divine revelation, and since the doctrine of Hell is logically inconsistent with some of the teachings of the Old Testament, we can reasonably conclude that either the Old Testament was not inspired by God, or else Jesus believed in Hell not as the result of divine inspiration, but as the result of uncritical acceptance of faulty human ideas about God. If the Old Testament is not inspired by God, then Christianity should be rejected. If Jesus believed in Hell as the result of uncritical acceptance of faulty human ideas about God, then Christianity should be rejected. Therefore, Christianity should be rejected.