There are millions of Christians like this in the US alone, let alone the rest of the world. I'm not sure what you're trying to push with your interpretation of christianity, but it's certainly not common, given that it assumes their god doesn't exist.
It’s hard to imagine who Augustine wrote his Confessions to or on whose behalf Galileo was killed, if all these people were just talking about metaphors.
If you built a power structure on top of a religion, or if you think that preserving respect to certain ideas leads to a more harmonious society in general, you can very easily prosecute people that undermine them, whether you believe them as real or not.
What I'm getting at is that it doesn't have to assume their god doesn't exist, as this is a negligible detail (implementation detail) on the respective worldview and its results in everyday life, culture, etc (not in the coarse grained debates in the US 15th-21th centuries, but in the course of 2 millennia of European and global history).