because you can't bother to learn and do research, actually. because you make the assumption that the council of nicea was competent and unbiased. that they weren't bribed to within an inch of their lives.

or, simply because you refuse to look at the world around you. this is made to be a struggle. in the garden we were given something that no one else had--free will. the angels don't have free will. that means that lucifer's rebellion was under orders and that all the rest of that suffering is a part of creation as well. god wants us to struggle and do our best.