I think Darwin matters because the theory of evolution gives humans something in common that can unify us all. The fact that we all share a common ancestor and evolved into a social species that relies on evolved morality to perpetuate a peaceful society can be something that we can all know and understand equally. We cannot get that from religion. One believer's god is slightly different than the god of his neighbor and very much more different than the god of his neighboring country. Believers are never on common ground even when they sit in the same church pews.

We have the ability to say morality is not what is deemed by the god of one's choosing but and evolved sense of what benefits individuals by creating a healthy environment in which we and our offspring can survive. We just need to keep saying it...they'll listen eventually.