Generalizing is a way in which humans navigate the many complexities of the world. We essentially cluster knowledge across a group of what we deem similar, and then apply that knowledge on a broader scale to what else appears similar. Generalizations generally keep us safe.
"Don’t eat anything not from the grocery store or equivalent (restaurant, farmer’s market, garden, etc.)" is a generalization most Americans follow. It keeps them safe from the very tragedy the raw foodist (there’s another generalization of "raw is better") experienced from the article David posted (http://articles.chicagotribune.com/2008-02-10/news/0802081267_1_yoga-north-side\
-friend_). A more specific statement than the above quoted could read: "Don’t eat anything not from a trusted source, unless you are truly (not arrogantly) confident in its identity and edibility".
Once a person decides to go down the road of identifying and trying their foraged foods we reach another layer of generalizing. Such a person might only forage for plants and not mushrooms, saying "mushrooms are too dangerous". It is true many mushrooms are very difficult to ID to the species. However, there are many mushrooms that are just as easy as the easiest of plants (of which it is always possible to be too careless and mistake a green potato fruit for a green tomato) to determine safety, such as giant puffballs.
Those who do forage for mushrooms fall in two [arbitrarily created] camps: Generalizers and Particularizers
Generalizers are those who seek out the easiest mushrooms, use a general rule, and then proceed to eat all they find that fits the general rule. Generalizer morel hunters, for example, learn the characteristics of morels, learn to distinguish them from false morels, and then consume lots of different morels w/o certainty about species.
Particularizer morel hunters will only consume those they believe they have identified to the species. Ironically, Particularizers, such as Particularizer King Bolete eaters, often end up not knowing what species they are really eating because they are going after a complex (cluster of closely related species).
It is another generalization to say "mushrooms are most healthful if eaten cooked". It is another rule that keeps us safe from problems such as acute harm of those toxic w/o cooking, long-term increased risk* (not guaranteed cancer, thus someone may consume lots of raw mushrooms for 80 years and be fine) of cancer (numerous journal articles do cite issues with eating certain common raw mushrooms), the possibility of harmful bacteria existing on the mushroom (such as Listeria monocytogenes, which is found on soil [amongst other things] and can cause a very dangerous infection for fetuses [http://en.wikipedia.org/wiki/Listeriosis]). We will return to the question of cooking later.
To return to the tree of generalizing and particularizing, another deeper layer emerges: Some people say: "I will only eat edibles I identify to the species, but never Amanitas". We have here another method of staying safe with mushrooming, not because only Amanitas are deadly, but because Amanitas are leading causes of mushroom deaths due to having both deadly and difficult to identify species that can be confused to the untrained and semi-trained eye (an especially difficult issue is when someone comes from one region only to find another mushroom in a new region that looks like what they’re used to eating, such as mistaking Amanita phalloides [deadly] for Amanita manginiana (edible). Yet there are also people who eat Amanitas safely for decades, despite others’ strong disapproval. Are they wreckless and lucky (true wreckless amanita eating, especially done often & w/o extreme luck, will likely eventually lead to death)? For the most part, they are people who have simply learned what is edible and what it toxic. These people have extensively Particularized down to species of a vast array of genera.
But what if we particularize instead of generalize about raw mushrooms?
*Assuming no other components are not one day found that reduce risk of cancer equally or more than the carcinogenic compounds do.