After being insulted and getting knee-jerk reactions, I stopped providing feedback when rejecting candidates. This is frustrating not just to candidates - who would like to improve their game - but also to me. At Babylon we were quite prescriptive with the feedback we were providing. We tried to be as neutral and constructive as possible. We would often provide more than 5 bullet points. Most candidates were thankful about this. We stopped doing this once we had a candidate being rude towards the engineers that interviewed him.
I have also stopped replying to applications, when it’s clear that the person didn’t read the requirements. We have plenty of people applying for a role that requires Python experience, even though they have none. Another example are applications that fall out of our timezone. We have a remote policy but within 5 hours from GMT. This is frustrating and tells me that we were just another place that the person applied to.