In the late 1990s, we grew shiitake mushrooms for a few years on oak logs in the shade of the piney woods around our yard.
We loved to eat freshly picked ones raw in salads.
I am not sure how clean purchased dehydrated ones are. However, I might consider try eating soaked dehydrated ones raw IF I were sure they were clean AND if I used clean water to soak them in AND if did not let them sit out too long at room temperature while and/or after soaking them --- BUT I am NOT recommending that you try this because I really do not know if it would be OK.
When you grow your own, you know how clean or dirty they are. When someone else grows them, you never know for sure.
I believe we McDougallers can have a loud enough voice to influence enough people to cut back on livestock consumption/farming that we CAN have a positive impact on global warming -- if we REALLY try!