There is definitely an inferred belief that a lot of people who are "extremophiles" are also more interested in the novelty of extreme things, or in posturing about having a deep understanding to show off rather than actually having that for its own sake. And I'm probably partially inclined to see that in others because I have a bit of it myself: I like cephalopods, but I have to confess to spending more fascination on huge and/or exotic cephs than the more mundane... although the more I learn, the more I come to appreciate the diversity more than the spectacular...
I suppose it's worth evaluating whether the belief that blue-ring enthusiasts are more likely to be what Greg calls "cranks" than any other ceph keepers, I doubt anyone's done a survey, but anecdotally, it seems like the vocal blue-ring enthusiasts tend to make an impression as being irresponsible, brash, opinionated, and more interested in being hear than in listening. I'm sure some element of this is that some of us (myself included) may come across as condescending when trying to make crystal clear what the dangers are in keeping these animals: I think it would be immoral to have someone interact with a blue ring without understanding the danger, so I tend to be very blunt in pointing out the dangers. This is partially because I'm very well aware of the action of TTX, since it's a standard channel blocker used in neuroscience, and because I have some background in emergency medicine, so, pet octopuses notwithstanding, I pretty much know the clinical aspects of injecting a small quantity of TTX into the bloodstream: acute respiratory failure from complete skeletal muscle paralysis. It doesn't seem unreasonable to me to say that this is not something that people should take lightly, or brush off by rationalizing "well, they don't cause problems very often..."
I tend not to take it particularly well when people get cavalier and posturing about things that are potentially extremely serious. I didn't like the guy on a dive boat bragging about how he'd disabled the safety on his speargun and how he never dives with a buddy (and I spent a lot more time watching out for crazy speargunners than looking for octopuses on that trip). I didn't like it when I saw/smelled some ski patrollers smoking dope on duty (and boy, did I ski carefully for the rest of the day...) I know plenty of people who collect exotic weapons of various sorts, and I generally find that the ones who make the show of bragging about them are the ones who are least likely to know how to use them properly, or to keep them responsibly, or to take care of them... I remember some guy lashing out to near my throat with some martial-arts move when we were both in a hot tub and announcing "I could have just killed you" out of the blue. At the time, I thought "yeah, whatever," but now that I know some people that are actually good martial artists, I also know that anyone who would do that sort of thing would be pretty much considered an amateurish ass in most respectable martial arts schools... I tend to see a lot of the same mannerisms in many of the people who are enthusiastic about keeping dangerous animals and disinterested in keeping similar but less dangerous animals, so I tend to (perhaps unfairly) assume that they tend to be cut from the same cloth.
