Why do so many of my fellow Christian reject God's oldest and most important laws, found in the Old Testament?

Do you know what these modern day immoral pseudo-Christians have the audacity to say? "Jesus took all that away." That is utter blasphemy, my friends! The very idea that the words of the Son somehow trump the words of his Father is nonsensical on its face. Do you think a Father who had spent so much time talking about killing disobedient children would allow His own upstart Son to tell folks to ignore everything His Daddy had ever said? I don't think so. If Jesus had even tried to do this, God would have yanked Him back to Heaven and given Him a good whupping with a rod. Jesus, Himself, admitted that he is subordinate to the Father who rules over Him (1 Corinthians 11:3). Jesus told the apostles that He had not come to destroy the law of the prophets of old, rather, He had come to fulfill that law (Matthew 5:17). Jesus approved of his Father's command that children who curse their parents are to be put to death (Matthew 15:3-4). Jesus chastised the Pharisees for failing to kill those children who defied their parents' commands (Mark 7:9-13). Jesus told us we are to live our lives in fear of God for God has the power not only to kill us, but to torture us forever in Hell (Luke 12:5). Jesus never contradicted his Father's word, and anyone who suggests otherwise is going straight to Hell.