This is also a reason why sometimes, while it might seem pointless, engaging in a discussion with someone you know won't change their point of view, can still be worthwhile. Because there's probably a huge number of lurkers who might either end up agreeing with you, or at least be deterred from simply agreeing with the person you're arguing with.

> "It's tough to get lurkers (like me) to speak up and shift the discussion when the emotional cost of doing so..."

the 98% works in that case too: there are many people who might benefit from your comments but don't interact in any way, so you sometimes may deem the costs worth it (like now).

> This parallels civic/political engagement in real life.

Indeed it does. And the "insane" label to the engaged is even more apt there.

This reminds me of when I attempt to send a Snopes link to someone who just forwarded me a chain email. They don't thank you, you get silence or worse.

Yeah, people don't like being corrected when they are wrong. I've bumped into that a lot when discussing things on social media. I find that if you can manage to spare someone's ego when correcting them, it helps a lot. Rather than sending a link and saying something like "You're wrong!" If I can give them the opportunity to decide for themselves that they are wrong, by saying something like "Are you sure about that, this guy is saying something different," I often get a better response.

There's a rabbinical art to being tactful that unfortunately eludes me. The effort is usually wasted on internet discussions.

In more controlled, personal settings my favorite response along that vein is "what factors did you consider that led to your conclusion?" It's a less offensive, more roundabout way of telling someone that their assertion is questionable that also betrays their thought process.

Silence from people who forward chain mails seems desireable.