The sun's radiation causes cancer, yet placing a blanket warning stating the sun causes cancer likely leads many to wholesale avoid the sun, which would be folly (humans need some amount of sunlight).

Similarly, imagine if nutrition facts labels only had to state whether the food could be potentially unhealthy, without any other nuance.

A sensible version of Prop 65 would acknowledge the specific substance, its dosage, and the best known safe dosage. Equipped with that information a consumer can make an informed decision.

And the flaw in that argument is that every product is made with many different chemicals, at least one of which almost always seems to be on the Prop-65 list.

Regardless of the strength of the evidence, which is yet another problem with the whole idea.