The Ten Commandments came out of the Old Testament.  They were replaced by Jesus with 2:  "Love the Lord, thy God, with thy whole heart and thy whole soul," and "Love they neighbor as thyself."  I don't know why people who call themselves "Christians" subscribe to anything in the Old Testament, as it wasn't written for them, and Christianity was instituted by Christ thousands of years later.  But I don't have a problem with the commandments.  No harm could come from following them.