Very true! But keep in mind for some children, it could be a sensory issue. I know of two kids personally who would go days without eating. I dare say a week or until hospitalization or medical intervention. And it's strictly sensory related. Not being a brat. Not being stubborn.
I have a similar story - I don't like the taste nor the texture of milk, and I never have. It makes me feel sick just thinking about it. When I was a kid my mom left me at a relative's house when she and my dad went away for the day. Said relative served milk with a snack in the morning. I didn't want to drink it. She told me "if you don't drink the milk you can't leave the table."
I sat at the table with the untouched glass of milk in front of me all day until my mom came to get us at 8pm.
My mom never left us at that relative's house again, as it happens.
I guess you could call that being stubborn and being a brat, but I didn't like milk enough that I would rather sit at the table all day while all the other kids got to run around and play than drink that milk.
People do often just think it's the kid being a brat or whatever and if you "cave" you're making your kid spoiled, and if you just hold out long enough that will somehow be magic and "solve" the problem. That kids aren't really capable of knowing what they do or don't like, obviously, they're just being obnoxious and if you're tough enough you can "win" the battle and your kid will be all the better for it. I think that's the wrong way to go about it and faaaaaaar underestimates children as human beings.
It tends to be people who don't have kids or have never spent extended amounts of time around them who think these things, IME.