Have you ever wondered whether people who don't believe in God or, at the very least, the reality of a spiritual world might actually be incapacitated in some way? Because if you aren't alive to the reality of spirit it means you have no real sense of the good or the beautiful or of glory or nobility or mystery. If you think these are just human constructs you can't be aware of them at all.
You truly think there is nothing beyond what you can see and touch, and that human beings are sacks of meat with bodies that are just machines and minds that are only like computers? If you have any real sensitivity you must be at least somewhat aware of the fact of spirit. Even if you can't quite believe in God because the religious presentations of him are outdated in many ways you should have some kind of sense of the spiritual behind the everyday. The problem of evil often brought up as a stumbling block to spiritual acceptance makes no sense. What about the far greater problem of good?
Are materialists people who simply lack imagination? Or do they just need to grow up? A bit of both, I would say. Then, of course, there are some who don't want to believe in the spiritual and we will leave their motivations for another time.