First, I referred only to the willingness of a person either to volunteer or fight without the military; not to whether they actually volunteer.
Also, to say that it's "not okay to comment" implies that it should somehow be a crime or a tort. Obviously I don't believe it should. You're free to comment on whatever you like, but that doesn't mean that your comment has any integrity or deserves any respect. (Much like the comments that guy from Duck Dynasty made about gays.)