It will be a good think when and if chocolate producers comply with California's MADL regarding Lead, I think, so long as this doesn't introduce other harmful substances.
But the same could well be asked of fruits and vegetables, which are generally except if lead comes from "natural sources" such as the water or ground. It has been reported that many of these would exceed the MADL otherwise.
Chocolate is not so exempt because it appears the lead arises not from the beans when they are picked, but afterwards from dust.
According to my calculation, one gallon of water in Los Angeles California has the same amount of lead as 14 bars of Hershey's Special Dark, the bar having the highest reported lead by Consumer Reports (2.65x MADL per ounce) in 1.5oz "Standard" (small traditional) size. Meanwhile, LA water is fully in compliance with federal standards, having less than half of the lead that federal law permits .
For San Antonio, where I live, water has only 1/3 as much lead as LA, so one gallon of water here only has as much lead as 6 Standard bars of Hershey's Special Dark.
I remember when there was a long eco-socialist drive (that persists a bit) against bottled water, with the message that tap water is fine. Maybe. I myself use Reverse Osmosis water, which I concede comes at some environmental and social cost. But it wasn't much for lead as much as Chlorine and Chlorine byproducts. But they also reduce lead, so a good idea in that regards also.
With the lead I'm saving from RO, I could eat a very unhealthy amount of chocolate and still not get that much.
BTW, 1.5 oz is probably about all you should eat in a whole day, or you'll have trouble not gaining weight as in Slick's Law (1 oz chocolate yields 1 pound weight gain). I can actually eat about 2 oz chocolate per day without gaining weight (and I'm fairly sedentary, except for my 40 min daily exercise, and I'm working on being less sedentary too). But if I eat 3 oz of chocolate, Slick's Law immediately kicks in, and I gain 1 pound of weight, and 2 pounds weight for 4 oz, etc.