[npinguy]

It's kind of how people are scared of dying in plane crashes but not in car crashes - the illusion of control. One easily imagines doing something to avoid a car death but not a plane one.

I think the same applies here: Death by starvation feels easier to avoid to a layman wilderness expert: forage more, hunt effectively, conserve supplies better, etc.

But death via an obscure chemical even while in possession of a book on edible seeds...that's scary and much more likely to give one reservations about their confidence.