I think he *does* believe it "as an American". The value in question is a strong veneration of the bill of rights.
He can venerate the bill of rights as much as he likes, but that doesn't mean that his being an American inherently means anything in the context of free speech. Americans as a group support plenty of views that contradict the kind of free speech the person I was responding to, and the bill of rights, support. Unfortunately it's a hard thing to have a rational debate about as there's plenty of American's so blindly patriotic that any comment that is less than flattering of their country gets modded to oblivion.