I had a black philosophy professor that went to Stanford. He got in the same year they started affirmative action, but he got in on merit. He was still bothered late in life that people assumed he was admitted as a result of that policy.
The main reason for the doublespeak is that it's illegal to racially discriminate. Had that not been the case, these people would have probably followed the professors advice and openly argued for racial discrimination
Not always - see Affirmative Action programs for some legal examples of racial discrimination. Also, the government has a number of programs that target/exclude people based on race
Yes, it's illegal if you openly say "Asians need not apply" but it's fine if you dress it up in the language of diversity and refuse to say how you actually get there. Even though the actual effects are the same either way. And so you get exactly what the professor describes.
He detested affirmative action.