That's pretty common recently for companies. I'm not sure why.

I have no idea how a commission-based business manages to do something like that.

Which makes this utterly weird - it was literally a matter of giving up (potentially) several grand by not forwarding an email.

I understand that, but when it's a purely technical decision they could easily enough give you constructive feedback.

You missed these two edge cases. Your code crashes on certain inputs. This is very inefficient, you could have done XYZ.

You could automate chunks of this, and protect yourself from any discrimination lawsuits by just making any engineer who reviews the code have zero knowledge of the candidate.

Because as a culture, we stop thinking of candidates as human beings the moment we decide we aren't hiring them?