Hey, thank you for that excellent link!
I think the situation is a bit confusing and confused, from what I've read on various websites. There are several separate issues that are getting lumped together. First, the lead content of the ceramic (or whatever you call it) that the crocks are made of, versus the lead content of the glaze that is actually in contact with food. Second, lead as measured by different types of tests with different sensitivity and accuracy characteristics. And third, lead content of the crock (itself, or the glaze) versus amount of lead actually IN REAL LIFE leaching out into food under normal operating conditions.
The only really meaningful thing IMHO is the latter, which I am having trouble finding information on. If anyone knows of any reports of tests done on this (e.g. lab tests of lead content of, like, tomato sauce cooked for 10 hrs in a crock, compared to the same sauce right out of its original container) I'd really like to see 'em.
However from what reading I have done it seems like any lead that is there is in the *pottery* not the glaze, so unless your crock is crazed or cracked (which is not especially safe to use at that point for other reasons either) it is not obvious that there'd be any lead exposure to food in the first place.
Note btw that it is perfectly reasonable for crockery to have some lead in it (not the glaze, the *pottery* itself), as unless you source somewhat unusual materials the naturally-occurring clays often have some miniscule lead content. This is presumably what's present in the crockpot samples being discussed.
Digression: I think it is good to look into these things. However, ya know what I mostly think? I think it is insane to expect food (or anything else in life) to be risk-factor-free. Never happen. You go looking for scary tiny risks, they are everywhere. Including in old-timey and organic-crunchy-natural-holistic things (botulism! uncontrolled varying amounts of plants' phytochemicals, many of which are toxic at some level! etc). I think it makes a lot of sense to research things enough to avoid obvious large risks, e.g. I do not use mexican pottery for food

-- but you can't go jumping at EVERY mention of a scary word, because an awful lot of the instances are going to be below meaningful threshold of effect and in any case pretty much EVERYthing you eat carries SOME risks of SOMEthing, and yet ya gotta eat
JMHO,
Pat