This makes even more sense when you consider why Dumbledore deliberately made Harry an outcast.
Think about it What would Harry have been like if he had grown up in the wizarding world? Or, to put it another way, what would Harry have been like if he had grown up in a world where magic was the norm?
He would have taken magic for granted. He would have been less likely (especially as he got older) to view Dumbledore as a wise mentor and more likely to see him as flawed and capable of bad decisions. He would have seen both the world and Dumbledore as ordinary, with their good points and bad points.
But Dumbledore didn’t need a well-adjusted boy who took magic and the magical world for granted. He needed a child who would love the magical world unstintingly, even irrationally, because it was a haven from neglect and abuse. Even more, he needed a child who feared this world becoming evil and who therefore would not question someone that he saw as the ultimate authority, especially if he believed that obeying that authority would keep the world safe.
Even if obedience meant his own death.
Dumbledore wanted a martyr who would die for the wizarding world, because he believed that Voldemort could not die until Harry did. Which was why he left Harry with the Dursleys and let them neglect and emotionally abuse him for the next ten years.
To get a martyr, he first had to create a victim.