I think that humans crave meaning because meaning is something that can motivate humans to do things that discomfort them even if subconsciously (i.e. wage slaving). Also, meaning can make humans want to live overall and continue the procreational ponzi scheme. Think about it like this, if you spent a lot of effort, suffering and anguish to achieve something and it means absolutely nothing, you'd be devastated and question why you even bothered to go through all that effort and suffering to begin with. However, if what you done has had a purpose to it, you can justify the irrational and discomforting parts of life that you're forced to do.
It must feel absolutely awful knowing that everything that you do is pointless and absurd (which is sadly our reality)