Specifically, filkertom was ranting about guns in National Parks and he used some language that got me ticked off. This isn't about the current topic of guns in National Parks, or about gun control in general; it's about saying "I think <the behavior we're debating> is insane". Actually, about SHOUTING it in all caps.
In your last edit you shout that the opposing viewpoint is insane, which if I were being entirely sensible would just make me quietly walk away, but unfortunately for me and anyone who's still bothering to read this thread, you've gotten me ticked off enough to generally mess up my mood.
Y'see, deep down inside, despite truly overwhelming evidence to the contrary, I really want to believe that rational discussion over time can lead people who disagree to change their opinions and come to an accommodation. Humans, in general, are not rational creatures; they believe and decide things based on emotions and to the extent they use reason, it's to justify what they've already decided, not to figure anything out. I find that ugly; I'm forced to accept it, but it makes me ashamed to be a human. In order to cope with that disgust, I really try to believe that at least some of us, some of the time, are able to actually be better than animals and truly use our rationality to decide rather than just to rationalize. And I hang out in fandom, with people I view as far more rational than the general run of humanity, so that I can cling to my illusion that humanity, though tragically flawed, actually has hopes of getting better.
When you say the idea you argue against in insane, you're saying that it's not merely wrong on the balance of the arguments, not merely very wrong or severely misguided, but so completely indefensible that a fully functional mind must reject it. You're saying that your opponent must be phenomenally successful in his debate to convince you that he's merely wrong and you're merely right, and you nearly imply that your opponent isn't actually capable of rational thought and therefore you have no reason to argue. There are some words that have no place in debate, and 'insane' is one. I didn't really pay attention to your inflammatory language when I first read your post; maybe if I had, I would have correctly gotten the message that you didn't want to have a discussion and I would have just ignored the thread, but unfortunately I didn't. I assumed you were merely using overly strong rhetoric -- as is unfortunately customary in political debate today. But with your last addition, you really succeeded in inflaming me.
I understand you already have a strong opinion, but if you're genuinely interested in rational discussion on the subject, or if you actually hope to sway the opinions of anyone who might be open to compromise, don't throw gasoline on the rhetorical fire by calling the opposing proposition 'insane'.
If, on the other hand, you are using the word with full honesty, you're admitting that your mind is made up and you're not actually willing to discuss it. In which case, let me go sulk in my corner, because you're one of the few people that lets me cling to my foolish illusions that human rationality is more than a misleading veneer.