In their defense, they probably have a very difficult time weeding out candidates that don't know anything about programming. It seems like this is the new alternative to a 30 minute phone screen, and I bet a lot of candidates actually like it. But it's good they have your feedback, and if they aren't too crusty, they will use your demonstration of knowledge in stead of your HackerRank score as proof you know your stuff and pass you on to the next level.