You are absolutely correct, Nova, and I appreciate your pointing that out ..... But by the same token, saying the argument is silly or simplistic does not defeat it in any way. I just mean it's not one of the recognized ways of invalidating an argument.
Separate but equal/Equal protection under the law:
The law would be unconstitutional on the basis of overbroad and a violation of free speech . . .
. . . but it would also be unconstitutional on the basis of enforcing against only citizens of one race. (I understand the LA City Council law bans all races from saying the word, but it's the same concept intellectually.)