I usually discern rational approach by the merit of the argument not because "someone wrote it on HN". If there is no argument but instead just blanket statements and negative remarks then I can somewhat safely assume that some thought process must've failed that person at some point - or at least I can gain no direct insight from it.
I'm not really a crypto evangelist nor anyone involved in it technically (at the moment) but I do know enough to at least somewhat understand the scope of the Idea - which is enough to never dismiss the whole thing based on some perceived flaw of some implementation.
It's slightly possible though, that HN commenters aren't approaching the topic of crypto significantly differently than other ones - but instead I just notice irrational comments more in relation to this subject - perhaps even because I know enough to recognize them easily. But it's very unlikely, even if true, that this would explain the whole thing away.
