It was a campaign video that reached seemingly every Democratic corner of the internet: former President Barack Obama’s 12-minute endorsement of his former vice president and indictment of the current president. On Obama’s Facebook page, one of the most popular destinations in politics with 55.3 million followers, his endorsement of Joe Biden was viewed more than 4 million times. But another Facebook page, run by twin brothers who immigrated from Mexico, reached substantially more eyes. Their reposting of Obama’s endorsement, with a simple “BREAKING” text over the video, clocked more than 23 million views. Meet Rafael and Omar Rivero, the...