[MikeTheGreat]

I imagine this differs from person to person, and that some people would find rejecting people (especially person after person) to be draining.

You're trying to hire because you want to find someone to help you and you're hoping this next person will be the one to be that help. The person looking for a job obviously wants to find a job that will work well for them, and especially during this pandemic it's entirely possible that the stakes are higher for them than normal (do they currently have a job? Are they moving out of fear of their job going away? etc).

I think that it's entirely possible that someone would find it stressful to reject a stream of applicants - repeatedly telling a series of people, to their faces, knowing that they're people and not just faceless applicants, that it's not going to work out might very well be stressful to some people.