A mere accident or unfortunate but correctible outcome

Our students’ ignorance is not a failing of the educational system – it is its crowning achievement. Efforts by several generations of philosophers and reformers and public policy experts whom our students (and most of us) know nothing about have combined to produce a generation of know-nothings. The pervasive ignorance of our students is not a mere accident or unfortunate but correctible outcome, if only we hire better teachers or tweak the reading lists in high school. It is the consequence of a civilizational commitment to civilizational suicide. The end of history for our students signals the End of History for the West.

https://www.frontporchrepublic.com/2016/02/res-idiotica/

Is the sentence in red grammatically correct?