The "software liberal" companies he lists - Facebook and Amazon - both make heavy use of C++ (a "moderate-conservative" language to Yegge) and Amazon also uses Java heavily (another "moderate conservative" language.
As usual with Amazon, though, this is an area where it makes more sense to talk in terms of individual teams than the company as a whole. Some teams build almost everything in Ruby and are open to new languages. Others are pure Java shops. Other than Infosec approval, it's really up to teams to decide for themselves.