My understanding is the policy is intended to avoid pointless debates and inadvertent legal liability (e.g. "when you told the candidate 'good luck with the new baby' at the end of the rejection convo, it created the impression they were not selected because they have kids.")
Why did he owe more feedback than "this isn't up to par?"
Based on past threads on HN I'm in the minority in preferring take-home projects and not feeling I'm owed compensation for the time it takes to complete them.
I like them because you have more of an opportunity to demonstrate your craft versus a standard leetcode whiteboard session where the 45 minute time constraint means you need to focus on pumping code out as quickly as possible. Also a good one can be an entertaining diversion in it's own right. Different strokes for different folks, I suppose.