On the right, we’ve grown to pride ourselves on our greater openness to debate and ideas, on having no need to toe a Politically Correct line or crawl into a “safe space” like pampered college kids who just can’t handle hearing from anyone who disagrees with them. For myself, I am so personally dedicated to this ideal that I even perform the great personal sacrifice of reading the comments field beneath my articles. Yet somehow I wasn’t surprised to see Donald Trump supporters, those swaggering tough guys, turn one of their favorite Internet forums into a safe space where they...