Ingesting an unseen flock of birds into an engine or two is human error?
Yes, today it can . In areas of known bird migration equipment and checking with people watching those birds know where they are , time , altitude direction , etc... Collecting and disiminated that info cost ressources and money. Someone somewhere has made the decision that this is not cost effective. Hence no detailed warning.
The Hudson A320 bird strike for instance could have been prevented, but at a cost. Probaly a big one, but someone ( a human ) has decided this was not worth the money. We can continue with more such examples if you want .
Yes. ultimately, whether it is FBW programmers, Certification aithorities, someone , a human, is behind. So 100% human error is not far off. That is also what Sydney Dekker is advocating today BTW.