If I can walk the walk and talk the talk, why can't I claim to be a Christian if it's important for some reason?

I finally let go of an all knowing, all controlling God several years ago. The fact that there is no God was the only answer to every question, and made such perfect sense that I had to acknowledge that it’s true.

However, I’m still the same person, and I can certainly talk the talk. I can raise my hands to heaven with an “Amen! Praise God!” I can still recite the rhetoric to “answer” people who have questions. I’m still mostly kind (or try to be) to people, and help out those who have less than me. I believe in the philosophies attributed to Jesus,and I can passionately reiterate them to people.
So, why can’t I claim to be a Christian, or imply that I am if I feel the need to, like if I was running for public office in America, say, mayor? Or senator? Or…President?