I bet the last thing Bernie Sanders expected upon his arrival in Ireland and Britain was to be met by angry protesters—to find himself heckled and damned as a sellout by the kind of radicals who would have been shouting his praises just six months ago. And yet that is what happened: Some of Britain's Bernie Bros have morphed into Bernie bashers. Why? Because he refuses to describe Israel's war on Hamas as a "genocide" and he doesn't approve of the boycott, divestment, and sanctions movement against Israel. Quick—cast him out. Unperson him. He has ventured outside the parameters of...