An actual organization called "Liberty Movement," though, could permit or prohibit membership as its board of directors (or committee or majority-rule or whatever) saw fit.
Hell, even encouraging such boards of directors to prohibit a specific person from joining is not automatically authoritarian, it's merely a suggestion based on an opinion. Of course, Morgan Freeman could invent his own organization and call it "Velvet Voices For Liberty" or something like that, and if such an organization gained more members than any other libertarian-sounding organization, that would be tough titties for all the detractors.
My own opinion is that Freeman is a sleazy NWO drone, but I will try not to waste any more of my life referencing him.
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