Earlier quoted context omitted.
There are countless places in life where people do elective activities that would be potentially deadly if they didn't have a base level of knowledge, and in none of those is the general expectation that people will make the cutoff "where the risk of that error is the lowest." Why? Because it's not that hard to figure out whether you're misestimating your level of knowledge if you actually do things to attempt that v…
You do a risk-benefit tradeoff. Here, the risk massively outweighs the benefit. So you have to be absolutely certain you're not mistaken. This is very different from activities with low probability risks and/or considerably larger benefits.
I know people who self-admittedly overcorrect and refrain from picking even a few easily-distinguished mushrooms that happen to be vaguely similar colors and shapes to deadly mushrooms, but the idea that you need to not pick any mushrooms at all, ever, in order to eliminate the risk is silly.
Picking wild mushrooms is not done (except by those who haven't done the trivial amount of info-gathering that is actually necessary) by gathering lots of different mushrooms and then identifying them and eating the ones that appear to be edible species. It isn't done by taking a field guide out and IDing mushrooms from scratch and then eating the ones that look like the edible ones in the book. It is done by learning species one or two at a time, along with all of their potential lookalikes. People who do this and start with easy mushrooms will encounter far more risk both from getting to the foraging area and from walking around in it than they will from the mushrooms.