Perhaps the non-religious people who are calling themselves Jedi ARE demonstrating their respect for the census process by calling attention to a question that, as formulated, at the least has little relevance to the modern day, and at worst is entirely incoherent?

Did it occur to you, when you wrote "you either under represent your religion or the non-religious", that you're taking on, uncritically, all the problematic ethnocentric baggage of 19th-century comparative religion, in particular the completely unwarranted premise that each person has a religion, one and only one, and one that the person themselves would identify as a religion, a distinct category of belief and action analogous to the religions of (then) contemporary western Europe. None of that is true. Alternatively, you may think that the idea that a person may be "non-religious" implies that one has consciously rejected a particular brand of monotheistic belief, a fairly benign thing to do in modern, secular society. Historically, of course, it has a broader and far, far more problematic meaning that facilitated myriad atrocities across the world, particularly against indigenous peoples. Even today, the range of beliefs that lie outside monotheism, or even the short list of 'official' religions (to which there is no common set of qualities or features, by the way) are so vast and complex that any reduction to a single category is utterly meaningless. I can tell you there's no box for my beliefs, but 'non-religious' is as inaccurate as any.

It's a stupid question, and it deserves stupid answers. I like knowing that people are answering Jedi because it lets me know there are people out there who intuitively feel that, and they don't care to answer one of the default categories just because it would be convenient for the census takers.