Indeed. I’ve always tried to send decent rejection letters but doing it honestly takes so much effort. Sometimes it just got to the bottom of my to-do list to die. You want to give constructive feedback to someone you met briefly and sometimes the reasons are really not kind: “we don’t think you are smart enough”, “we didn’t like you”, “having seen your blog we are worried you are not able to be professional enough”.
This is true feedback a manager might have, or the team has voiced. For most people sending that verbatim is scary as hell. Wording it respectfully but also staying honest takes a lot of mental energy and is still scary. Over the years you build some muscle memory and thicker skin for it, but some copy paste templates of respectfully written rejection letters would be a great resource for hiring managers.