Dilemma of the day: correct someone who is being stupid, or let them continue?

Someone on Facebook posted something warning people about this urban legend in earnest. If he were a real friend, I think I'd correct him, totally politely of course. An aunt had a habit of sending out e-mail forwards, as did someone I knew through my previous job. In both cases I sent them a link to Snopes saying what the "official" word on that was, whether ambiguous or not. In both cases I'm pretty sure I was civil about it, or at the very least I'm definitely sure that they accepted my e-mail with good grace and didn't send me anything else like that. However, that's an aunt and a kind of aunt-like figure. This guy, in my experience, ranges from well-meaning but annoying to just annoying. So I'd take more pleasure in correcting him, but on the other hand I don't want to remind him that I'm still alive. I don't need awkward questions about where I'm living or anything.

As it is, I'm torn on whether or not to comment on Facebook about it. However, I'd be almost certain to ignore this if not for the fact that two days ago I heard something similar and did nothing. In line at the Post Office Saturday I heard some moron telling a young kid he was with about how it's a sign of how government sucks. That's illogical at best (what, specifically, are they doing wrong? Would FedEx get through that many customers any quicker? It's stupid to use a sample size of one office on one morning; how long is the average wait overall?) and leads to politics like Tea Partiers and the Bush years. I didn't say anything because I was just picking up a form from a stack and was about to leave, why make a scene in public, a retort that wasn't sufficiently to the point would just make myself look stupid, etc. And, of course, the long wait was annoying.

So because I regret not saying anything about wingnut stupidity, I'm now more inclined to way something about stupidity of a less politicized variety.