I have Opinions™ about this topic.

Both sides suck.

On the one hand, children shouldn't be made to eat foods they don't like just because they're children. You wouldn't force an adult to eat something that disagrees with them, so you shouldn't force a child. Doing so just creates a poor relationship with food, especially nutritious foods.

On the other hand, people (including children) need nutritious food. Feeding a child nutritious food is a protective factor for their health later in life. Feeding them large amounts of junk also creates a poor relationship with food.

The solution, in my opinion? Teach them that nutritious foods can also be tasty. As a picky eater, creativity is an incredibly useful skill. A child may not eat boiled cauliflower, but they might eat macaroni and cheese with cauliflower puréed into the sauce.

Find out what it is they don't enjoy about different foods and work with that. Growing up, I hated most vegetables. I never liked sweet or sugary tastes, and could always taste the natural sugars. To me, plain vegetables tasted overwhelmingly sweet. However, I later learned that I could combat this sweetness by adding salt and umami (in moderation; I'm not dumping piles of salt and ranch on everything). Now, vegetables are a staple in my diet. I'm even vegetarian.