Weeks after NBC granted Hillary Clinton the favor of appearing on "Saturday Night Live," playing a bartender to the actress who impersonates her on the comedy show, the same leftist activists who adored that routine are trying to prevent Donald Trump from hosting the show on Nov. 7. A group called "The National Hispanic Leadership Agenda" has written a letter to NBC objecting to the booking. MoveOn.org has organized a "Dump Donald Trump" petition drive with hundreds of thousands of leftist signatures. Another petition on Change.org also drew a leftist throng through social media, aided by the hashtag RacismIsntFunny. The...