Interesting rhetorical move. What other kinds of communications are you in favour of censoring?
I think it helps strengthen the argument rhetorically, since people can't as easily use the existence of such "exceptions" as an argument for adding more, or bypass the principle entirely with slogans like "freedom of speech isn't freedom of reach". (Suppressing the "reach" of certain ideas obviously does inhibit their free exchange.)
This approach hasn't been "battle tested" yet though so we'll see how it goes in practice.