You seem to brand honest misunderstanding as FUD sometimes. I think that's a mistake, given the original intent of the FUD concept, even when, in a literal sense, there's at least uncertainty and doubt in these cases, whether or not there's fear. (Note, this is an impression, I haven't done any sort of an exhaustive survey. I just think that your metaphorical FUD-label-gun has a hair trigger and you an itchy finger.)

That being said, when people repeat complete nonsense as fact without even testing it, there's rarely a reason to be particularly gentle. And I think most all of us have limits on our patience for certain misunderstandings, which vary from individual to individual. So, I certainly sympathize with the sentiment even when I disagree with the approach.