Gov't mandates for labeling have to be based on proven risk though, otherwise regulators are literally just guessing what is a risk and what isn't and/or they would be forced to have warning labels almost everything produced. The "better safe than sorry" excuse doesn't really work here, because excessive labeling can counter-intuitively harm the public for many reasons. Here are a few that come to mind:
1) People get overwhelmed with seeing labels and they miss or outright ignore warning labels for actual proven risks, which increases public health risk
2) Labeling requirements can stifle development of new technologies and science that can have very real public health benefits
3) It costs more money to regulate and produce goods that gets passed on to the consumer. A little extra cost may not matter much for unnecessary/luxury products, but for basic foods, medicines, etc. higher cost can be big public health issue.
4) In our global economy, other exporting countries might not bother complying with onerous labeling requirements and just not offer their products, which ties into #2 and #3 above.
5) When gov't public health policies are not based on science it makes it much harder to change policies and act quickly when there is a scientific consensus. Or another way to think of it... anti-science policies dilutes all of science, which can hurt everyone (see also: anti-vaxxers).
I'm not against mandating labeling of products when it's based on science and proven public health risk, but the anti-GMO folks aren't there yet. Unfortunately, sometimes it's impossible to identify a risk particularly long-term risks until something used for a while. So, while there are awful examples like DDT, agent orange, asbestos, hormone therapies, etc. the important thing is that gov't has the ability to step in and stop them when the risk was proven (see point #5 above).