statics

No, it's not a strong indicator that the process is random or worthless. That makes the assumption that the people rejected by the process would have scored just as well. It could be very good at determining who has the technical skills to work there. It might be that their performance scoring of hires is measuring something else- like how much their manager likes them.

A few very bad assumptions there: 1) not all employees have CS degrees from the US, many are foreign 2) the graduation rate by "race" or "gender" in 2015 is not what is was in 2005, 1995, 1985 or 1975, and the any industry has many people who graduated a long time ago. Comparing current year demographics to the industry as a whole seems really off. 3) Due to historical economic status which is correlated with race, more of those that started off less well off tend to gravitate towards more stable companies.

None of these things mean that negative racial discrimination or stereotyping don't exist, just that we shouldn't expect numbers for a particular industry population to match the aggregate stats on who graduated last year.