I understand that, but your comments presuppose that the only time a consumer would actually trouble himself or herself to read a label is at the point of purchase. Frankly, everything is taken to one's home. There's abundant time to read even extensive labelling at home and perhaps to alter shopping patterns in the future.
I don't see, frankly, a downside to imposing on manufacturers an obligation to be rather fulsome, to use that tired word, more fulsome or detailed in their labelling, rather than compressing it into something that can be read in one or two seconds only. People, I think, will be curious after they've purchased exactly what it is that they and their families are eating and they'll have abundant time to read the label very, very carefully once they're home.