Sorry about that awful experience we caused there. We definitely had a period where we simply struggled to respond to everyone. We honestly get about 100 emails from this HN listing. When we were just a few people, it was hard to keep on top of. It's a poor excuse, and we're fixing it now (we genuinely get back to everyone now). We didn't handle this well for quite some time, though.
Use resumator or one of the other cheap apps for handling this. For most people a canned response is absolutely fine, it's the no-response that ticks people off.
We do make sure to respond (and provide feedback if asked) to everyone who applies. The issue that we're working on is our response usually comes 2-3 weeks after the initial submission.