The "supermarket" white mushroom ( Agaricus bisporus ) is the same as: white mushroom, button mushroom, champignon mushroom, cremini/crimini mushroom,[4][5] chestnut mushroom, And the portobello/a.
Just because you can eat a few species raw doesn't contradict the statement the virtually all require cooking.
I'm just saying that I have never heard that cooking was required/recommended to make any mushroom safe to eat. I had assumed they were either safe, or not, and cooking them was a separate matter, mostly of preference.
There are varying degrees of preparations to be safe for various mushrooms. There are a few you can eat raw. There are a few that will kill you even if you cook them 10 times. And there is everything in between - from mushrooms that you cook once, to those you need to cook 3 times, replacing the water each time and ventilating to not inhale the vapor :))
Source - 30 years of experience foraging and learning from grandmom.
There are only a handful of species that have been eaten raw enough times to be generally regarded as "safe". Crimini/button mushrooms being among them, as well as king boletes.
Caesar's Mushroom (Amanita cesarea [1]) can also be eaten raw, if you're making a list.
Note that it's not present in US/Canada which do have the common (and commonly considered poisonous) fly agaric (Amanita muscaria [2]), which can appear a lookalike to the untrained eye.
As advised in other replies, your local mycological society is likely to organize course on identification, foraging field trips, run id clinics, etc. so a good initial step for folks wanting to know more would be to look for local expertise.
Portabello seem to be more dangerous than the general public realizes, though Paul Stamets doesn’t want to go into detail. Some suspect this type of mushroom is highly carcinogenic. Either way, cooking the portobellos at high temperatures should make them safe for consumpion.
First I've heard that -- I eat raw white "supermarket" mushrooms (sometimes portabella and shittake also) in salads quite often.