There are definitely people who feel like this, but I'm with your parent poster -- I do not want to have an uncomfortable conversation with you about why you're not giving me an offer. This isn't a breakup. We weren't dating. You can just send me an email.
especially when it's just an offer/rejection. we aren't talking about a layoff.
I’d guess they opt to do so not just to give you a chance to provide feedback but also liability.
It's oftentimes better for both parties when rejecting someone to do it via email. The person being rejected isn't put on the spot to compose themselves and be a good sport while the person doing the rejection can manage the response from the person getting rejected (don't have to immediately answer follow ups and/or defend their decision).