But, even then, a lot of FDA mandated labeling is neutral. If I am told how many carbs or how much fiber my cereal has, it is neutral, because all other cereals have those ingredients.
Not true. There are plenty of products on the store shelves with labels like "Fat Free", "No Added Sugar", "12g of Fiber". These are being used to target a subset of customer that may not include you, but it is intended to communicate something about the value of the product to those customers motivated by these labels.
For example, the label "Natural" implies that their competitors products are somehow unnatural. That is how the "Organic" label started out. In order to bring clarity to the consumer space the USDA instituted the National Organic Program which defined what practices and ingredients could be used and remain eligible for the organic label. These kinds of certifications cost money, and they wouldn't spend the additional money if people weren't willing to pay a much larger premium for products bearing the label.
Whether harmful or not, as a consumer, I should know where my food comes from.
You have EVERY RIGHT to ask, but unless there is a valid health/safety reason the vendor has EVERY RIGHT not to tell you. I'd like to know the exact recipe for Coca-Cola Classic. Right down to the mg. Doesn't mean the Coca-Cola company has to tell me, or that I can use the FDA to force them to release that information without good cause. Same goes for GM foods. You can choose to only buy products where companies disclose on their labels the GM status of all ingredients, but that is as far as your rights go unless there is a valid health/safety reason for you to know.
Assuming the products are indeed safe (and I have no reason to suspect otherwise), shouldn't they be labeled like everything else and those companies wanting to produce them educate the population? After all, if they have nothing to hide with GMO, then why hide that it is GMO?
Lets unpack this a little. First you are correct that the products are safe. Otherwise the FDA wouldn't have approved them (that is their job after all).
Second, you are approaching the labeling discussion from the "Why Not", when in fact the FDA must approach it from the other side, as in "Why Should They". As I pointed out above, there is a cost associated with labelling (supply chain segregation, verification testing, certifications, inventory management and demand projections, etc.). These costs may seem trivial from the outside, but as someone who's been involved in this stuff at work I can assure you that they are anything but trivial. Under the law, if the FDA is going to institute a new policy they need to conduct an economic analysis to determine the cost of their new policy and the benefits. Mandatory labelling of GM status has NO MEANINGFUL UPSIDE, and as all cost. Voluntary labelling on the other hand requires does not require this economic analysis, and can be supported through user fees (those seeking to get the label pay for the federal expenses associated with overseeing the label).
Now from the consumer side, it is perfectly reasonable to request that AquAdvantage label all of its GM salmon, and based on the unprecedented levels of transparency the company has demonstrated thus far, it is entirely possible that they will. I, for one, would like to buy their salmon to support them and say a big "FUCK YOU" to the anti-science fear mongers out there (plus I like salmon!). However, that is a MARKETING decision, not a SAFETY or REGULATORY decision. As someone who has had direct dealing with the FDA, it is very important to make sure they don't put my products at a disadvantage by trying to make marketing decisions for me. That is my job not theirs, and in my experience they are not very qualified to make those types of decisions.