For a serious answer, there’s a whole process you can follow. It’s basically going from minimum exposure up through eating a small bit of it and waiting multiple hours to days between steps. If any show signs of being irritating or worse, don’t eat/use that plant. It’s slow enough that if you had to rely on it for finding your sole source of food, you’re going to have a rough, hungry time.

Something like:

1. Rub a little on hardier parts of your skin, wait and see.
2. Break up the plant to expose more of it and rub that on a small patch, wait and see.
3. Try it on more sensitive skin areas, wait and see.
4. Try holding a bit in your mouth, spit it out. Wait and see.
5. Chew some up, spit it out and wait and see.
6. Eat a tiny amount, wait and see.

I’m probably forgetting some steps, too. It’s genuinely very slow.

Worse yet, there are plenty of plants/fungi that would still fuck you up or kill you doing it this way, so the OP still has a point.