Without easy access to the relevant information? I mean how would the average customer know from the Amazon page or from even using the product that there is 751 times more lead than allowed in it?
If the distributor was required to test the product and put a large red banner "might induce lead poisoning" on the product page, then of course the consumer could choose. Alas, that's not the case.
Why should that responsibility rest on the distributor's shoulders and not the original manufacturers?
If people were deeply concerned about lead, shouldn't we expect that products that can offer such a guarantee have a market advantage? Amazon et. al. make product attribute comparison pretty straightforward.