Just to weigh in on the other side, I don't think it's unreasonable for law firms not to provide feedback at the application stage. This is quite normal for companies.
I do appreciate it's very frustrating for applicants, and I can completely see why. You spend so much time working on your applications and going through the tests. Equally, from the side of a business, it's more time (with a small team) on people a firm has decided not to progress. There would need to be some type of reason to provide feedback (e.g. if you feel the person is likely to reapply with a stronger application or just slightly missed the mark.)
I know it can feel like it's just one more thing they need to do. But each of those emails invites a lot more queries, especially given the volume of applications they receive. People who get rejected are also more likely not to take the feedback on graciously (as is the nature of feedback), which is why it is often generalised.
I say that as someone that used to hate the feedback I used to receive. But it is also easier to see the other side now.
