Reactionary as I learned it in school was not perjorative.
It referred to someone who, as a rule, condemns what we have in favor of what we had in the past. Perhaps someone was using the term with a sneer on their face and that's where the "distaste" comes from. I know I experience that distaste every time someone uses the word "liberal" as a synonym for traitor, idiot, Marxist, or whatever the flavor of the week is.