JM, I think Roger is using the term somewhat ironically, as do a lot of us old-school liberals. “Reactionary” means (as I understand it – haven’t checked the OED yet) someone who dogmatically defends the old order, old beliefs, old power structures, etc., and “reacts” negatively against change. Formerly employed as a term of abuse by the hippie generation, it now fits many of those same self-styled “liberals” and “progressives” perfectly.