Why do professed christians disobey the simple commands of the bible but hold fast to man made doctrines?

Are you truly one who seeks Gods aproval & are a diciple of Jesus if you flat out do things you know is against the law of God but will embrace the things that has infiltrated true christianity? Why? Matt 7:13,7:14,7:22, 10:22,15:3,Col 2:8,Heb 10:26