Hi,
Frank did something that is much more appreciated in Europe than it is in America. Over there, there is an incredible history of dissent and opposition, that ended up differently. In America, the dissidents were wiped out, be they the orignals that were here before, or simply another part of the country.
Thus, the types of satire and humor that Frank used was not quite enjoyed in America, to the point where many people still listen to it and say they hate it because of the words, or whatever ... never mind the subject.
Comedy, even in England, has a very naughty history, for example, and even Peter Cook and dudley Moore did their thing for the "royals" and the "upper class" parties, since they both were from the very same institutions that they all came from ... and you can hear some of it as "Derek and Clive" ... and it is not any cleaner or safer than Frank Zappa. Even though I do not have much other comedy, it is hard to imagine that there is no such "naughty" stuff in France and Germany, where oppositions to this and that can be, usually, very bad. In France, there was a very large contingent of political carttonery and buffoonery during the days of the guillotine ... so you know that some of the stuff was around, that even the guillotine could not kill!
Once you get over the words and letters, the whole thing can get funny, weird, strange ... like any other comedian, despite some of the material not being ... this or that ... like today, so many folks would attack both of these to the ground until they were dead. And kill the art ... again.
But as Daevid said, you can kill his body but you can't kill him! And the same goes for material that is true to its source and ability!