The hiring process isn't just about the candidates you make end up hiring. Everyone that comes in contact with it is going to form an impression of your company

The hiring process isn't just about the candidates you make end up hiring. Everyone that comes in contact with it is going to form an impression of your company--positive or negative. Clearly there's some kinds of feedback that is likely to leave a negative impression (see those that threatened violence!) but on the hand putting someone through days and days of interviews and then saying "we didn't feel a spark" also is going to leave a negative impression. The rare interviews where I received concrete actionable feedback afterwords, even though it still stung I have a more positive impression than those where I got some pabulum (much less the ones that ghosted me).