Hm. Well, why would it be?
Originally Posted by MildSteel
[[It is worth noting in this context that SCOTUS has said that it can be, but in reverse - specifically in the context of written tests for advancement. Blacks, I suppose, they felt, were too stupid, or too incapable, or too 'something' to succeed on their own, and so tests which produce "disparate impact" are illegal. That is less "discrimination against blacks for having lower group IQ scores" than it is "discrimination against non-blacks for having higher group IQ scores", but it seems germane to the question.]]
The kind of discrimination I can see being justified is usually surrounding questions of security. For example, I believe it is insane that we insist on searching 80 year old grandmothers from Idaho on our "random list" while waving through Abu McJihad returning from Yemen after his adult conversion to Islam. That is a form of discrimination that I think is justified because of the competing rights involved. One example pertaining to blacks (though not to intelligence) also pertains to security. Young black males in large cities tend to have a hard time hailing cabs at night, as cab drivers perceive a greater possibility that they will be robbed. This came out a while back and everyone was quick to cry "Racism!" until we found out that black cab drivers also avoided picking up young black males at night in large cities, perceiving a greater possibility that they would be robbed.
Not knowing the stats on cab robberies at the time, I don't know how well I could defend that rationally - but the important point is that both are cases of discrimination based on risk, which I feel can be legitimate (see first example). That is also why I oppose the application of "disparate impact" rulings especially to functions that deal with security, such as fire-fighters and police.