I'm not sure what you mean here. One can advocate for or against "free speech" and whatever it may ultimately include or not include without having to invoke a specific United States legal framework which doesn't apply in many (most) contexts. Freedom of speech as a right of humankind has existed as a concept since long before the US did, the US merely enshrined in its constitution that the government should generally not infringe on it, with very limited circumstances in which it may do so. This is, in my opinion and that of others, a good thing. Where those lines are to be drawn is largely up to the courts, and is often the subject of debate among both jurists and laypersons. 

I guess my overall point here is this: there's no reason you can't say "free speech is an important right that we must protect" without invoking any specific legal doctrine, if that's what you believe. That statement can easily apply to any government agency, private corporation, public corporation, or individual citizen, and be broadly relevant. Once you invoke the first amendment, you're now limiting the context of your advocacy.