Outrage has become the signature emotion of American public life.

People are so used to it—the noise, the flying spittle—that they were pleasantly surprised when Rep.-elect Dan Crenshaw of Texas declined to be incensed. He is the former Navy SEAL who lost an eye in Afghanistan and was mocked—more stupidly than viciously—for his eyepatch by a performer on “Saturday Night Live.” The insult called for outrage, in the usual tit-for-tat. But instead Mr. Crenshaw took it in good humor. He went on “SNL” to accept the performer’s...