Even the best mycologists can be wrong. ... I am in the school that all wild mushrooms have risk.
Sorry but this just sounds totally paranoid.
Theoretically you are right. Paxillus involutus and Tricholoma equestre are the two examples. Their classifications have changed in 1950's and 1990's, respectively, and there is still a risk some mycologist or author just does not principally agree with science but gives dangerous advice because of their emotional attachment to said mushrooms. Yet, the reason their toxicity was discovered as late, is because they are fine in 99% of cases if not more. So you would need to:
* Ignore modern books; ignore to double-check; ignore to Google
* Eat them many times while never Googling,
* Still have extremely bad luck,
to become sick or die.
Of course it's a fair assumption that
intelligent life must exist outside of Earth, too some mushroom species believed to be safe turn out to have very rare reactions with 0.001% of people; i.e., Tricholoma equestre all over again. It's just that science goes forward, life expectancy of people goes up, and this is more and more improbable every day. You can further reduce the risk to basically zero by eating the most well known and widely used species.
But, even if you buy pre-processed food, vegetables, meat, etc. from the supermarket, in the end, there is a real non-zero risk it's accidentally contaminated with some poison or some super microbiological hazard. Or, while visiting the store, you get COVID and die, even if you wear FFP3 mask taped to your face.
Or while in the forest, picking mushrooms, a wild bear comes and eats your head.
We can theoretize that
everything carries non-zero risk, but average people normally ignore this, and it's sensible to do so. Benefits of living your life outweigh the tiny risks. Just avoid
actually risky behavior; in case of 'shrooms, this would be eating all mushrooms without identifying them.
But indeed, if you assess the suitability of food based on what you see squirrels do, you are doing it all wrong. Very wrong.