I work on OpenFoodFacts, and the big issue is simply the amount of saturated fats and refined sugars there are in a lot of processed foods.
Like, sure, people have to be held personally responsible to some extent, but it should also be on the government to properly regulate how foods are advertised. I really appreciate the Nutriscore system that's being pushed for in Europe despite the flaws it has, and here in Canada they've been making some changes in how certain products are shown on shelves such as requiring labeling if they're high in sugar or fats and changing the previous confusing labels for energy drinks with a more easy-to-read Supplemental Food Facts label.
End of the day though, if something is still being labelled as being "healthy" when it really isn't, that's all it takes to fool the average consumer unfortunately. Stuff like Lucky Charms shouldn't be advertised to kids as "part of a complete breakfast", and it's absurd that a lot of "healthier" alternatives to certain foods are being advertised that way despite only being barely any better than the original product, like turkey bacon or veggie straws.