Just saying life has no meaning so everyone can just create their own meaning makes no sense from a materialist viewpoint. If everything we are is pure matter acting according to predictable laws and patterns, then that should make it easier to derive a recipe for creating a satisfied society, and imposing such a system will perform better than giving people meaningful choice on the matter. And a purely hedonistic Brave New World type of society might be superficially pleasant but in the big picture would amount to a horrific rotting away. Science, technology, art, and civilization itself at their core require some level of faith to keep them progressing.