How can biology by a point of view?

Christians say, lets teach creationism and evolution side by side, so then I can choose what I want to believe. That is like saying tech me that 2 + 2 =4 and 2 + 2 = 6 and I will decide what one works better for me. Evolution is true and is backed up by science. There is no debate about the validity of evolution in the scientific community. It is accepted as true because that is were the evidence points to. There is no evidence for creationism, not even the smallest amount. And for those that say evolution is only a scientific theory, well, so is gravity, will you denounce gravity next? Will you say, let me choose if gravity is real or not. Let me remind you that creationism is not backed up by science at all. I guess the question is, why should we teach two different views in school, when one is true and the other is not?