We used to give specific details for things (ie, price is going up because x). People INTENTIONALLY misunderstand, selectively pay attention, and argue endlessly.
Same thing with job interviews and hires. Imagine a potential hire for a client facing role with poor communication skills. If asked point blank about any areas of challenge in their application you might say this was a high pressure customer facing role and so communication skills, as described in job post, would be a big factor in the analysis. You might then be repeatedly followed up and both re-assured by them that they have excellent communication skills (with lots of bad grammar, spelling errors and terrible tone) and threatened for evaluating them on their skills in this area (which may overlap various protected classes).
People sometimes take the worst possible interpretation of any action and nitpick every explanation. Read hackernews for plenty of examples here.
In many cases, particularly if someone is not paying you - it's really not worth getting into it with folks who love to argue endlessly. They usually have FAR more time then you do, and if you have 20 people arguing with you an entire day can be lost dealing with them.
If you send an Email with some reasons, you're not required to spend hours defending your position. But giving some feedback is beneficial to the applicant and potentially also to yourself because you're forced to think about the reasons and keep a record which might also be useful.
You screen 100 resumes - you talk to 20 people. If you give quick feedback in the response for those 20, and do 5 positions in a year that's 100 quick pieces of feedback - I agree - would be totally useful.
Didn't have required license, communication skills weaker, not familiar with industry, not local to area etc etc. I could do these very quickly.
BUT it only takes ONE person tweeting and being offended by the response to cause huge problems even BEFORE you get to litigation risk and folks going back and forth on topics.
Imagine this - even job references in the US have gone to almost no content. "Giving a negative reference may expose the company to legal liability if the former employee does not get a desired job and decides to sue for defamation or slander. But providing a positive reference or failing to disclose potentially damaging information can leave the company open to legal liability (negligent referral) as well." - Result - again, just very little info is disclosed.
Sometimes folks have an axe to grind or lots of time on their hands (unemployed).
I used to work at a prominent venture capital firm where I started an initiative that required everyone on the investing team to respond to all inbound emails from founders, even if the reply was "Sorry, this isn't a fit for us." We tried for several months to respond with atleast 2-3 sentences about why we passed on companies if a founder ever asked. About 10% of founders said 'Thank you, that's useful' and moved on, another 10-15% straight up said "You're assholes" but moved on. The remaining majority were just incapable of understanding what we were trying to say since they were so sheerly blinded by their self-belief. Example, I remember emailing one founder of a poker game app back to say we didn't invest in gaming, only to receive an angry email saying poker isn't a game, it was a social activity. Thinking it would help, I replied saying 'Hey, thanks for the note. Really, our issue is that gaming apps and apps where the primary social activity is gaming, are very hits driven and we don't think we have the necessary experience ore desire to predict hits in this space.' He then proceeded to tell me why I did in fact have the skills required, even though literally no one on our team had consumer or gaming experience, and that I in fact also did have the desire to predict hits in this space - how could I not?_____"I was a VC after all"_____(direct quote)
A few months later, cold inbound emails that were passes went straight to archive...
Occasionally we would get questions back. There is a point at which you have to stop answering questions, though. We're not a tutoring service. At that point we'd just say something like, "We don't have any more detailed feedback other than what we've given you. Good luck on your job search" kind of response. We never got beligerent replies from candidates, but sometimes got them from recruiters.
The recruiters are the real problem because they will sometimes (some of them even often) demand "partial payment" for candidates that they thought were "good enough" but who we rejected. We had to write a few strongly worded "Our decision is final and we believe it is justified" letters to those recruiters. Saying that we won't accept any more candidates from the recruiters if they persist shut up most of them, but not all of them.
Eventually we gave up using recruiters anyway because they were essentially giving us random candidates. I think if you can find good recruiters and you can build up a good rapport with them, this kind of feedback is as useful to them as it is to the candidate. If you can't, then you are better off without them.
So, if anyone is wondering if it's worth doing, I would say that my experience is generally positive.