The purpose of food labels is to increase safety, transparency and honesty around the contents of food. Companies who oppose safety, transparency or honesty and/or produce products with questionable contents will oppose labels and companies who support safety, transparency and honesty will support them. I don't know many end-consumers who oppose labels themselves. But they will oppose products that contain questionable ingredients, so transparency is bad for companies that produce those products.
Not quite.
Companies who can use the official labels to back up their own advertising campaigns will support them. (I know people who think that having a label for something is evidence of that thing being good or bad. No, it's evidence that someone thought that expending the effort to convince the government to have that label would have a positive return.)
Companies with more ability to amortize regulatory overhead (relative to their competitors) will support them, because for then that overhead is itself a competitive advantage.
USDA Organic label is rampant with fraud, and just having thr USDA label on it isn't a guarantee of trust. Similarly, the AHA endorsing oils blatantly bad for the heart is also similar example how labeling doesn't promote trust necessarily. Labels can and do lie, quite often even.
You will never, ever get that. It's simply impossible. Label games are the biggest legal tug-of-war between consumers, regulators, vendors, and the industries.
When I began reading about labeling and its regulation, and all the bullshit tricks that are played to "stay compliant" but also lie out their asses to the consumer, and hide everything from us, I concluded that there is no way to truly read a label properly.
It basically comes down to a question of whether you trust this vendor or provider to give you a quality product. If you do not trust, then do not purchase. If they play games and lose trust, then do not purchase. Once you have a decent-sized blacklist, then there is no reason not to patronize those survivors.
Oversight is then called for (eg USDA organic) which itself can still be frauded around, especially when dealing with sources outside of the US.
I'm reminded of a tiktok that had raw chicken labeled with a particular weight at Walmart. When they weighed it on a checkout scale, it didn't match the weight the label had. On multiple packages.