I think the thinking behind not asking about your background and looking at your resume etc - is that these things can introduce a bias. By asking for particular types of questions and training their interviewers in a particular way they are trying to reduce bias and streamline the whole process.
In the truest sense of the process, an interview and hiring/not hiring decision IS discrimination. You are selecting for traits you (in theory) want, and (in theory) rejecting traits you don't want. Well, you are doing it if your interviewing process is not broken.
If you simply try to elide all bias, then you would never be able to make a decision.
