That’s actually a very valid point. Take-home assignments not only require a significant amount of effort from the person administering them but also from the interviewer (or rather, the hiring team). After investing the time and effort in reviewing a project, it’s reasonable to expect feedback/a response back if requested.
However, we must also acknowledge certain realities. If there are 20 solid candidates for a single open position, many capable individuals will be rejected. This doesn’t imply that they were inadequate or even “failed.” It’s simply a reality of life.
Now to be asked to justify why a hiring manager picked A and not B, legally speaking, cannot be that I had to pick one out of the amazing candidates, so I picked one. The legally correct response (unfortunately) is to get nit picky and find faults where none really exists. At least, that has been my observation in how corporate America likes to operate. And last time I checked, Kagi is based out of Palo Alto.