Why are private test problems randomly assigned? Why can interviewers choose problems they like?
To improve ease of use for interviewers and to make cheating by some candidates harder. Unscruplous candidates can always sign up and assign tests to themselves from the private pool. But without knowing the size of the pool and without being able to choose individual problems, they cannot be certain that they are prepared for all possible problems they might face in a future test. Of course no online test can prevent cheating absolutely. Cheaters are, however, caught right away in personal interviews. A personal interview is always recommended before making the final decision to hire.
