Because it really isn't that simple that a food is either healthy or unhealthy. So many different factors to consider.
For instance many people claimed on another thread that factory made sushi, factory prepared fruit and a bottle of pop was "healthy".
The sushi contains white rice that has been sugared and salted with only a tiny amount of veg, but lots of Mayo in comparison. The fruit will have been made in a factory a week ago, dipped in chlorine and packaged with special gasses to prevent it from looking degraded but it will have lost lots of its nutritional content. A bottle of pop usually just contains a huge amount of your daily calories from sugar. So I wouldn't consider this meal either healthy or unhealthy. Probaby 95% unhealthy a d 5% healthy. Lots of sugar and processed carbs.