I always swore to myself when this happened to me that if I was ever in a position to change this, I would.
I did. When I became the Director of Administration for a Federal Agency, within the first two weeks I had every HR person in an all-hands meeting. We discussed a lot of issues. What worked. What didn't. And I implemented a requirement in every single person's Performance Plan that required timely notifications to all applicants during the recruitment process.
Every complaint was investigated. Corrective actions were put in place. We implemented automated notifications. You got one when you applied. You were notified if you were referred for interview or not. Once a candidate was successful, we notified that person first. Quickly thereafter all others not selected received notifications. It allows people to have closure and move on. I don't understand why any employer is reluctant to let folks know the outcome. It's only common courtesy in my mind, since they took time to apply for your job, right?