The Hellfire doctrine is for sure a God dishonoring teaching but we are not judges as to what is blasphemy and what is not!<quoted text>
Are those teaching eternal torment blaspheming God? What about those who claim they have cast out demons by the power of Gods Holy Spirit, are they endanger of everlasting destruction by God?
As far as casting out demons Jesus and his Apostles did but is unlikely any have the ability to do that today by means of God's holy spirit. Remember those who had the ability to cast out demons also could raise the dead.