Why do Christians claim that they don't have to follow the Old Testament anymore?

They are Christians in name only. All of God's commandments still apply, and I see no place where any of them have been suspended. All of God's commandments conform with the natural law so then most of your religions are just plain stupid. The biggest joke of lamestream Christianity is the idea that the commandments are not important. This is an utterly absurd and stupid doctrine; and God is not stupid. The commandments are the only thing that works; none of their religious rituals have any benefit. The scriptures have been counterfeited and so the doctrines have been twisted to fit a satanic agenda. The only duty of a man or woman is to keep God's commandments.