If you take the assumption that this Supreme Being has to be the God in the Bible (or any other religious text) out of the equation, I think at least some non believers would be more likely to agree.
I think there are multiple forms of evidence pointing to the existence of a Supreme Being creator.
You make an important point. The choice between Christianity and atheism is not a binary one, but it is interesting to ponder how many people have turned to atheism as a reaction to the Christianity that they were taught as a child.A false premise many secular people have is that Christianity must stand on its own to be "appealing" to believers. In classical theism and Christian scholasticism historically, one STARTS with proving (to himself) whether or not a "God" of sorts exists using philosophy and logic. It is only once the answer is determined to be "Yes" that you can start wondering what that God/being is like. It is this next exercise that leads many people to Christianity. If you ALREADY do not believe in a God of sorts, the Resurrection story seems incredibly difficult to believe ... but if you have reasoned yourself toward theism in the first place and this is now your starting point, the claims of the New Testament are not exactly difficult to accept.