The basic reason why Yale doesn't want this information easily accessible is because it would force them to acknowledge that many of the staff are brilliant researchers and absolutely lousy teachers.
This notion that thinking freely about tough problems, and having the ability to pass your knowledge down the generations go together isn't true in the hyper-competitive academic environment today. If a professor doesn't publish, he/she can lose tenure, but if a professor doesn't teach well, he/she can have more time to publish.
I think the best universities to learn are those where the professors truly want to teach. Where their research isn't an end in itself, but a way to inspire questions for another generation. Yale seems to be asserting that it's not in this category.