You’re absolutely right, though I want to suggest an addendum more than a disagreement. I suffered quite badly with ARFID (avoidant/restrictive food intake disorder), and for people like me I think there reaches a point where the conventional wisdom begins to backfire. I was showed what ‘real’ healthy food looked, felt and tasted like… and I was disgusted by it and wouldn’t go near it. My diet suffered massively as a result, and for some ARFID sufferers it’s much, much worse, with really serious health complications.
What helped me start work to get over it was getting to a point that I could feel ‘safe’ eating badly, that I could live that way without pressure or serious health risk. Once I had that feeling, it became possible to start working on introducing one new food at a time, which has added up over the years to being mostly recovered. I don’t think I would ever have got here simply from continued exposure to (and pressure to eat) stuff I couldn’t face.
So generally, you’re absolutely right and children should be introduced to a wide range of healthy food. But in edge cases, I think it’s amazingly helpful if people struggling can find really healthy ‘safe’ things to eat.