There's a difference between not knowing and knowing but still choosing to do the activity.

I ride a motorcycle, and I am fully aware of the dangers involved. I also know that going the speed limit, wearing a helmet, and not drinking anything will significantly reduce my risk of death, but that it's still more dangerous than driving a car.

At the same time, I know that breathing in sawdust, paint fumes, and many other things is dangerous for me, so I have a mask that I wear when doing work around my house, and I ensure that there is good ventilation. The "cost" of doing those things is small compared to the possible benefits, so I do them. And without the information that those things are dangerous, I would be putting my wellbeing at risk for no good reason.