No, the statement that was made was, "The only possible good use of a Mac, is to run Linux on it." Plausibly the poster might have had reasons other than moral considerations for making such a statement—maybe they really prefer Xlib to Quartz, System-V-style system calls to BSD, or Nautilus to Finder—but I doubt it. Apple's unethical and abusive treatment of their users seems more the more likely rationale for such a statement, since running Linux has historically been the escape route from such practices.

It's legitimate to protest against injustices and menaces to human rights even when millions of people accept those injustices and don't recognize those menaces.