It's misleading to talk about healthy foods.
There is a healthy diet for a given individual, which might involve, e.g., a calorie surplus, consistent sodium intake, low residue, low fodmap, high soluble fibre, low sugar, gluten free, low protein, high salt, whatever. And there's how any individual food fits into a person's diet, including both long-term and immediate needs. Sometimes the healthiest food is a dose of pure glucose.
It's not that easy to classify a particular food as intrinsically healthy or an unhealthy, unless it's actively harmful to anyone who eats it in any reasonable amount. A food can only be healthy or healthy insofar as it interacts with the health of the individual eating it. Even when it is harmful to anyone who eats it, if the alternative would be an inability to afford sufficient food, then it's not so cut and dried. If the only food somebody can afford might give them kidney disease in thirty years, then they need to eat the food. The fault isn't in the choice made, it's in the choices available.
Where there are foods or ingredients that are harmful, they tend to eventually get banned or restricted in some way. It's perfectly reasonable to campaign for awareness of ingredients or foods you believe fall in this category. It's also reasonable to campaign about industry trends which lead to the promotion of unhealthy diets. The argument needs to be clearly targeted at the problem in the food supply and the industry's incentives and marketing. But very often, the tone people use makes it seem more like they're criticising the person eating it for not being as clever or as rich as them.
Saying that a bread roll isn't even food because it has a few additives you don't understand comes across more like snobbish mock horror than any kind of sane argument about unnecessary detriment to health. It's so hyperbolic it's hard to take seriously, and makes it seem like you're looking down on people for being stupid enough to eat something that isn't food.