With all due respect (truly!), you are missing the point.
The point is: scientific arguments fail to convince because the issue escapes the scientific domain. The question is not "do we naturally tend to do X, Y or Z", but rather "at what point and to what extent are we ethically obligated to seek out people different from ourselves?"
The point is: scientific arguments fail to convince because the issue escapes the scientific domain. The question is not "do we naturally tend to do X, Y or Z", but rather "at what point and to what extent are we ethically obligated to seek out people different from ourselves?"