The FCC’s crackdown on televised profanity has broadcasters of all stripes running scared, even staid old PBS, which usually has more to fear from conservative activists than it does from the threat of indecency fines. Specifically, PBS has changed the rules for the award-winning documentaries that have long been a staple of its programming, excising profanity wherever it occurs, even in the mouths of soldiers caught up in World War II. Documentarian Ken Burns, for one, can’t believe the new prudishness.