Oh, come on. The myth (whether true or not) is that Buddy Holly (and other early rockers) were "hated" for singing rock at a time when it was considered "African-American" music (to put it nicely) or just play "Satanic." There are scenes about this in the movie bio, to take just one example.
Every sane person now sees this early hysteria about "demon rock 'n roll" as silly and most now see Holly as a great songwriter. So whether she is historically accurate or not, the "hatred" of Holly to which the song refers is a badge of honor and very much to Mr. Holly's credit. IT'S A COMPLIMENT IN THE CONTEXT OF THE SONG.
Some people (and I don't mean just at this forum) are twisting themselves ever' which way to demonize the Chicks and for what? A half-dozen or so words about the worst president, possibly ever? Strange priorities.