So if a college education is just a proxy for those other indicators, wouldn't college also have the same disparate impact? If it didn't, then it wouldn't be a good proxy. I might be missing something key here.
Can you elaborate a little?
A college degree is not evidence of no criminal record, only a very good positive signal (as the % of felons with a college degree is very small, I suppose). Claiming that an employer requires a degree as a proxy for criminal background check would get you nowhere in a discrimination lawsuit, unless you have solid evidence (recordings, documents, confession).
And college (and all schooling here in the U.S.) likely does have a disparate impact, but it is not the same as jobs. Schools don't hire students. We have universal education at least for K-12, and colleges have scholarships and the like to enroll more minority and lower-income students.
"More important, not only do students enter college with unequal demonstrated abilities, but those inequalities tend to persist—or, in the case of African-American students relative to white students, increase—while they are enrolled in higher education." http://chronicle.com/article/Are-Undergraduates-Actually/125...
The problem with college is that they aren't doing a good job at actually educating students (see the above article about the book Academically Adrift). Faculty at most colleges, for example, are never even trained in how to effectively teach - they lecture. Research has shown that engineering students in traditional lecture courses are twice as likely to leave engineering and three times as likely to drop out of college compared with students taught using active learning methods. Active learning also results in twice as much learning as lecture methods. (http://www.whitehouse.gov/sites/default/files/microsites/ost...)
And the problems at the K-12 levels include things like no universal pre-school, which could decrease inequity, and the lack of learning and high number of dropouts in high school.
Even if conservative criticisms of 'disparate impact' are right (http://www.nationalaffairs.com/publications/detail/the-dead-...), there is still the moral problem of inequality. Do we just accept racial/income differences as unchangeable or inherent to humans, or do we actively try to improve the situation.
People are much more likely to complain about losing out of a job if they go out of their way to take an job related aptitude test as compared to being pre-screened out for not having a college diploma.