That's an ancient (in internet terms) problem, framing Reddit as some sort of intentional ideology-spreading-loss-leader-for-powerful-capitalists doesn't correspond with their actions - after all, Reddit has been deeply involved in the spreading of all sorts of ideas on all ends of political spectrums.
They're just running into the same issues all these "give something cool away then hope you can make it profitable later" business do of trying to turn the revenue knobs slowly enough to not drive everyone off.