Why isn't feeding junk food to children illegal?

Hello There!

So we are all pretty much aware that junk/fast food is not good for our bodies, yet many of us proceed to consume it. It's no surprise that it is addictive, but not just because "it tastes so good" but in a lot of cases it contains ingredients which cause an addiction. These could even be "natural" ingredients, such as sugar or certain fats.
Why do parents choose to feed this so called "food" to children?

Children who cannot even speak, do not really have much choice of what they put in their mouth, they do not understand that it is not good for their body and their brain. What they do know is how to spit out food that is disliked. I have seen mothers feed babies under 12 months snacks such as quavers (made of potato starch, similar texture to prawn crackers), which are high in sodium and filled with flavour enhancers (just like most of foods/snacks nowadays).
These ingredients are more dangerous to us than we think, and to be quite honest I do not care that much when adults consume it because they make a conscious choice. Unless they're totally unaware of the food's poisonous effects, then I think they should be informed. However, feeding babies who do not have any idea about the food's "unhealthiness", but they crave it because it "makes them feel good" should be highly unacceptable and frowned upon.
I theorise that babies who have been eating unhealthy foods since they were little, will be less likely to eat healthy options such as food low in refined sugars, bad fats and sodium.

Sometimes, when it comes to slightly older children (up to 6 years old), parents seem to be "obeying" to the child's nagging and crying for junk food (i.e. when in a supermarket). One thing that could be done is to explain to the child clearly that the food is bad for their health, and to develop respect for their body and mind. Developing understanding in children is very important, and we should restrain from thinking "they're just kinds, they do not understand". Obviously their capacity is more limited than our, but it is expanding. Not explaining things to children and refusing to answer their questions could be harmful for the expansion of the knowledge and craving for it. Even though it can be tiring as some children ask a lot of questions, we should be happy that they want to learn about life and how it works, instead of just learning from books and whatever they tell them at school.

Do you think it should be illegal/punishable to feed children, let's say under the age of 10, unhealthy foods (i.e. high in fats, sugar and/or chemicals)?

Thank you for reading!