I think its more a lack of faith point though. Christening is all about being officially welcomed to the church community and through the ceremony you will be asked to promise to ensure the child religious edumaction - are you willing to do that even though religious faith (no matter what form) is not important to you? Its an empty promise iykwim?

There are lots of different ways and rituals to welcome a child into the world. Naming ceremonies are big in the non religious community. They can be really, really lovely - there are lots of celebrants that do this type of thing, I've been to heaps!