Yglesias talks about how "taking time to help inform a non-specialist audience about political science findings isn’t specifically rewarded, it’s positively punished." This is actually how things go in many parts of academia! And it's a big problem.
It's a problem specifically for progressives because a lot of the areas where they're concentrated have exactly these norms against doing public intellectual work. Meanwhile, economists are free to go out there and mostly spread right-wing dogma across the galaxy. And it's a problem for everybody, because you'd want the knowledge that's contained in academia to find some way out. Lots of resources are expended on producing this knowledge, and the personal advancement of academics is all about creating more of it, and then nobody has any way of accessing it.
(I'm lucky that my philosophy colleagues at the National University of Singapore perfectly fine with the political stuff I do. It's an interesting dynamic, because most of them aren't Americans, and they seem to think it's pretty cool that my big extracurricular activity involves trying to get the US government to do reasonable things.)