Balsamic vinegar, unleaded please!

Today I came across the following sign while shopping for aceto balsamico:

   The red wine vinegars and balsamic vinegars on these shelves contain lead,
   a chemical known to the state of California to cause birth defects or other
   reproductive harm.
Wait, what? Of course, by now I've searched the tubes and these signs have been there for quite a while. And it's widely discussed too, and people go on raving about these bad vinegars and if there are good vinegars and so on - but I did not find the answer to the question: why? Why would anyone still buy lead-containing vinegar, when it's clearly stated that it's harmful to the (human) body. Well, for Californian bodies, that is. As if lead was not toxic in other states :-)

I don't get it. At all.