Why shouldn't religion interest atheists? Religions are practically universal in history, which means if you're interested in people, you're interested in religion. And our species is social, so we're interested in people. No mystery there.
I incorporate existential philosophy into my worldview, so I'm inclined to agree that theism/atheism is more of a heart than a head issue. For example, I've written that the arguments for or against theism are irrelevant (some links below). The deeper issues are ethical and aesthetic, in my view. So I'd argue that the Christian myths are stale fictions, in which case they should be rejected as stories that no longer speak to us in late modernity.
Your question about "proving" Christianity seems to me confused or misleading. Descartes spoke of "proof" of God, too, because he was a mathematician. But Aristotle was closer to the mark in saying that different disciplines call for different standards of evidence. You don't prove anything in ethics or aesthetics since those areas aren't like mathematics.
If we're talking about the historical question of Jesus's life and death, critical (somewhat scientific) historians have already worked out the relevant standards, and they don't help Christians in any way. There's no chance the available evidence of early Christian writings and of the early church, and so on could support the belief that a miracle occurred in the first century, not on historical rather than theological grounds. You'd need to add the assumption that God works in history, but that assumption would violate the methodology of the critical/objective/social scientific (as opposed to the credulous, ideological, overtly religious) approach to history.
But I think you're asking whether atheists want Christianity or theism to be false. A more precise question would be whether the world that corresponds to atheistic naturalism would be better or worse than the one that would correspond to Christianity. I think you'll find from my writings on Medium that I don't sugarcoat the implications of atheism, unlike many of the scientistic new atheists. I'm more of an old-school, existential atheist. I combine naturalism with dark pantheism and cosmicism, for example, and I regard godless nature as fully monstrous (links below).
