Why aren't atheists as uniform in doctrine as Christians?

Why can't atheists be like those folks from the paragon of uniformity known collectively as "Christianity", where all members of the Christian cabal uniformly agree with all the beliefs and doctrines of the Amish, the Holiness Church, Mormons, Jehovah's Witnesses, Nazarenes, Baptists, Catholics, Coptics, etc? That is why when you ask any two Christians a question about salvation, baptism, Jesus, sin, Biblical meaning, or anything else you always get identical answers from them.