I believe it’s also because it’s easier to access. It is way cheaper than buying healthier options, it’s quick, and you see it more often (such as vending machines, most food at grocery stores, fast food, commercials, etc.). It can also be addicting, like getting rid of chocolate or soda on your diet. It’s just overall more convenient economically and to save time, as well as hard to get rid off because of the limited options you have when it comes to healthier food, whether that’s by time taken to make, price, taste, or even how long you can keep it for (healthier foods tend to not have as many preservatives).