The at times vulgar heckling and booing that greeted Johnson did not drown him out, though he was hard to hear because he spoke to media microphones, not through loudspeakers.“As Columbia has allowed these lawless radicals and agitators to take over, the virus of anti-Semitism has spread across other campuses,” Johnson said from the steps of the university library, calling on violent protesters to be arrested and threatening to cut off federal funding to universities that fail impose order.Johnson, whose job as House Speaker has been threatened by ultraconservative Republicans in…