Because MORE regulation is just what is needed here. Right. The gov's job is not to be a nanny, and as such doesn't need to be involved here. If people are going to do something, then they should live with the outcome of whatever is they choose to do, whatever that may be.
As long as the regulation is only to force the retailer to disclose all the nutrition information about the food, but not actually prevent its sale, then it's good regulation and something the government should be involved in. Its job is, after all, to protect its citizens from all threats, both foreign and domestic.
That way, the consumer can actually make an informed choice, rather than just buying something based on sight alone and hoping it's not going to give them a coronary. If people choose to eat this garbage despite seeing what's in it, then that's the point where it becomes their problem.