The attack on the U.S. Capitol by an angry mob of President Donald Trump’s supporters shocked many Americans who thought such a violent assault by their fellow countrymen wasn’t possible. But for Oklahoma City bombing survivor Dennis Purifoy, the Capitol assault was a clear parallel to what happened at the federal building in his hometown more than 25 years ago. The anger against the government, a radicalized perpetrator fueled by right-wing extremism, a desire to spark a revolution — all commonalities with Timothy McVeigh, whose fertilizer truck bomb ripped apart the Alfred P. Murrah Federal Building on April 19, 1995,...