I got into this in a response to a question about preparing children to be slave owners and those who study Disney films and slavery in popular culture can provide additional context but want to respond explicitly to one part of your question.

Virtually every white child living in the American south before the Civil War was raised to view any Black person they encountered as someone's property. In effect, white parents worked to ensure their children saw enslaved people as less than, even those who helped raise or care for them. One of the ways to accomplish this was through demeaning or childish nicknames. At the same time, white women tried to create the public perception that the institution of chattel slavery was gentile and something that took advantage of what they (racistly) claimed was Africans' nature and willingness to serve. Calling an enslaved woman "Aunt" sits at the intersection of those two fundamentals of white supremacy: enslaved people were less then and slavery wasn't that bad.

To borrow a bit from my previous response, white children were raised to be slave owners. Enslaved people were regularly given as wedding gifts or to celebrate the birth of a child. This meant white children were witness to their parents' acting as the owners as enslaved people - including separating enslaved children from their parents, assigning work tasks, and enacting punishments when work was done to the white person's satisfaction. White children and young adults were frequently an active part of the decision making process around punishment. In one recorded instance, a white mother scolded her teenage daughter for being too harsh when beating an enslaved child as it might render the child useless. They were taught to ask enslaved adults they saw out and about what they were doing and did not bother with the polite necessities they were expected to use with white adults. Basically, white children knew a Black woman named "Aunt" wasn't really their mother or father's sister.

So, in effect, there was nothing controversial about chattel slavery for white children. Black men, women, and children would come into and out of their life based on their parents' needs and whims. Rather, the controversy came when white children grew up and walked away from the institute of chattel slavery. The Grimke Sisters are the best example of white girls born and raised to be enslavers who walked away and spoke up about the inhumanity of the institution.