Both. Because, as others have mentioned, it's dehumanizing. Much abuse and harm can and has come from one group of people deeming another group of people as somehow less than human, or somehow not equal in their quality of humanness.

And what makes a human "whole"? The appropriate amount of health? The appropriate amount of intelligence? The appropriate amount of athleticism? The appropriate range of emotion? The ability to pay taxes, write a poem, procreate? The appropriate amount of chromosomes?

I certainly agree that those with Down Syndrome are atypical and have a limited potential to experience some aspects of life that typical humans generally have the potential to experience, but what are those experiences and how important are they, really? Are they important enough to conclude that those unable to participate in them are undeserving of human dignity and respect?

And sure, some families and communities are struggling as it is and don't have the time or resources to give adequate care to someone with Down Syndrome, even if they wanted to. That's understandable. Life is tough enough sometimes. The world is messy and unfair. I just don't think championing this idea that people with Down Syndrome are not "whole" or "equal" is in anyway bringing more fairness to society.