The short answer to this question is that there are a lot of unnatural and, in some cases, unhealthy chemicals added to make the product look like the selling image. For example, Kraft Singles are sold as yellow squares of cheese because yellow is the color that everyone associates with cheese. The chemicals that are used to create the illusion are yellow dyes numbers 5 and 6, which have been proven to cause hypersensitivity, hyperactivity and other behavioral effects in children.
The FDA has received complaints regarding food dyes, due to the health risks that have been researched extensively by scientists using lab rats. The results are unpleasant to say the least, and it can be surprising to find out what foods have these dyes and what health effects are linked to each of them . Blue 1, for example, is linked to the brain. This dye is found in colored beverages such as soda, candy, and pet food. Red 40, a dye commonly found in baked goods, cereal, beverages and candy, caused mice to have tumors that attacked their immune system and caused hyper accelerated allergic reactions in consumers. These are just a couple of examples from a long list of dyes that have been proven to cause negative reactions. There are natural dyes that are made from unaltered material that food producers have yet to implement. Some companies might not want to change their policies if natural dyes are too expensive to use for mass production, or if the foods don't retain their usual color and the change causes them to lose sales.
People have the right to know exactly what goes into the food they’re eating, especially if the ingredients are known to harm them. All of the facts can be found online,but when it comes down to it, the general populace will be in the grocery store looking at the calories or the price, and not necessarily paying attention to these dyes, which are a hazard that hides in plain sight.