"If you make your child lunch at home, you don't have to pass health inspections and wear hair nets and gloves. You don't need special training."
Think of school lunch as an analogy to public school in general. It's prepared by people who have special training for it and who are required to follow all kinds of regulations. They work hard and they have to prepare food for as many as several hundred kids at once. They have to make sure every kid is served, even those with food allergies or a disability. The food meets certain nutrition standards and is probably healthier than junk food, even if the kids don't really enjoy it.
On the other hand, it's not great food. At some schools, it's downright awful; at good schools, it's usually just passable. And even when it's good, it's not tailored to your child. They might serve your child green beans when he's willing to eat vegetables only if it's broccoli in cheese sauce. Or they always serve chicken fried when he loves it baked. They don't have time to pay attention to his individual needs. They're too busy trying to feed hundreds of kids at once in a limited amount of time.
"It's not an insult to the people who make school lunches to say that your kid is better off eating at home"
If you make your child lunch at home, you don't have to pass health inspections and wear hair nets and gloves. You don't need special training. You don't have to figure out how to serve 500 kids at the same time while using up the food that's been issued to you by the government. You don't have a time limit. You only have to know that your kid will eat broccoli but not green beans or that he wants his chicken baked. And you can make sure he's eating good, healthy food, because you're making it for him every day and you know exactly what he's getting.
"So why is it controversial to say that a large classroom setting is an inefficient way of teaching compared to personalized, caring, one-on-one instruction at home?"
School lunches are fine for parents who can't cook or don't have time. They keep the kids fed, without poisoning them or making them sick. They serve an important function for kids who need to rely on them. But that doesn't mean they're better than home lunches, when kids have parents with the time and ability to prepare them.
It's not an insult to the people who make school lunches to say that your kid is better off eating at home, because they're providing an important service to large numbers of kids as best they can. It simply isn't possible for them to make food that is right for every child, no matter how hard they try. A parent with the time and the ability to cook can almost always make a better lunch for their child than the school cafeteria, because they can meet the child's individual needs.
I think few people would disagree with this assessment of school lunches. Most people who went to public school think the lunches were awful and would rather have eaten at home every day. So why is it controversial to say that learning can work the same way, that a large classroom setting is an inefficient way of teaching compared to personalized, caring, one-on-one instruction at home?