A guess on why Slavery, Indentured Servitude, and Transportation aren't properly discussed in the US

It makes people uncomfortable to think that someone's ancestors didn't come to the US willingly. Slavery, indentured servitude, and transportation run against the narrative of people coming here for the "American Dream". Unless you mean the American Dream of someone else who receives cheap labour.

The US is far too in love with its national myth of opportunity and unlimited resources. The narrative runs that people come to the United States because they can work hard and enjoy the benefits. The reality has been that people work hard and someone else gets the benefits.

Tell someone who wants to know your ancestors immigration story that they came over in chains as a slave and they get all uncomfortable.

And Transportation is something no one is willing to talk about, but I would scream out my convict heritage like an Aussie boasts about being an ancestor of the first fleet if I found out one was in my family tree. But people also get really uncomfortable when they find out that a lot of pre-Independence immigrants were felons.

Bottom line is that unwilling immigrants aren't what people want to hear about.