I learned about this video from MediaIte, which headed it: Ann Coulter Rails Against ‘Speech Nazis’ at Trump Rally, by Josh Feldman, August 25th, 2015. "Rail", like "rant", "spew", "spout",  and "screed", is only used of speech by conservatives. (Tellingly, Rich Lowry once used "screed" to describe something Tom Tancredo had written.)

Ann Coulter is not ranting or railing here,  she's speaking, and the "speech Nazis" are people like ABC corespondent Tom Llamas, who interrupted a Trump presser to say  “Are you aware that the term “anchor baby,” that’s an offensive term.  People find that hurtful …” Trump swatted it away. Ann suggests "anvil baby" instead, because that's what they'll be around the necks of the taxpayers.