zero ability to guarantee stability.

There you go with the black and white viewpoint again. Racial tensions just exacerbate overall tension (ideological, economic, religious, etc.), and those tensions lend themselves to instability and infighting. Removing one cause of social discord helps ameliorate others, and keep a common social fabric more intact.

Demographic shifts have made Americans overall unsuitable for the demands of liberty in the Constitution. Those of us who can handle its responsibility individually will lose freedom because of these shifts (as well as general moral degradation, which also seems to have a disproportionate source).