That is where you are wrong. Hell is a punishment for sin, not unbelief. The reason unbelief is a sin is that it is inexcusable for a rational creature not to realize there is a Creator to submit to, the only position that gives objective meaning to life. Unless you are incapable of thinking rationally, atheism and agnosticism are sins. As for pagans, their gods are morally flawed, unlike Jesus. We instinctively know that God has to be perfect. That is why their religions permit or command evil, like burning widows or sacrificing children. God will forgive those who repent of evil, but will punish those who don’t.