Agreed! Except in american (and increasingly global, english-influenced) vernacular the words "conservatism" and "liberalism" have begun to stray so far from their "original" meanings that they can no longer be trusted to accurately convey meaning.
What? In America liberal is very much displaced from its "original meaning".
Except is used more like an interjection there (agreed, except that...). They didn't mean to except the american vernacular from the rest of the sentence, just to clarify why they didn't write "conservative" in the first place.