SETH BARRON is the The Post’s Associate Editorial Page Editor, and the author of “The Last Days of New York” and the new book “Weaponized: The Left’s Capture and Destruction of America’s Sacred Institutions ” (Humanix Books, out now) . In the adapted excerpt below, he writes about weaponization and the current political landscape. We have heard a lot about “weaponization” over the last few years. On social media, it has become a kind of shorthand, like the word “gaslighting,” for anything that