Not very much compassion if they let them die at 6 which would be expected when their clan realized they couldn’t hold their own and left them to die.

Sounds more like these academics are putting their own feelings into their research than anything. Do you honestly believe neanderthals even knew what Down’s syndrome was? They probably just saw all of the other 6 year olds taking care of themselves and this one was just slowing them down, if anything this just confirms they take care of all children until a certain point.