It's overstated by the fans. Gene Roddenberry was a lib with a very utopian vision of humanity's social evolution - he recognized that no poverty meant no capitalism, but he didn't really have a coherent idea of how it got there or how it maintained equality. Just that at some point the nukes started flying and then we met aliens and then we got our collective shit together. So that's why Trek is often extremely lib despite the foundations of its universe implying the existence of galactic communism.