Assigned to cover the re-election campaign of Gov. Ron DeSantis of Florida, Miles Cohen, a young ABC News reporter, found himself stymied. The governor would not grant him an interview. Aides barred him from some campaign events and interrupted his conversations with supporters. When Mr. Cohen was finally able to ask a question about the governor’s handling of Hurricane Ian, Mr. DeSantis shouted him down — “Stop, stop, stop” — and scolded the media for “trying to cast aspersions.” The DeSantis campaign then taunted Mr. Cohen on Twitter, prompting a torrent of online vitriol. So on election night, Mr. Cohen...