Well, they didn't quite say "don't use them," but the point is they really haven't been proven to be safe for pressure canning of low-acid foods in particular; this is really a very important subject and while I think it would probably be fine for anything that can be safely water-bath canned, I would not trust it for things that need pressure processing. Sorry, but I would rather be a little fanatic about this than get sick from something I canned (or worse yet, have someone else get sick from it). Botulism is nothing to mess around with
