[rab] It's what publishers have to do all the time, but still not pleasant to be in the judgement seat. Do you know, or are you likely to meet, this person?
[rab] Count yourself lucky that the editors are sending you such good papers. In my field at least, rejection rates in the top journals run 90-95% or so. I certainly have to recommend rejection much more often than acceptance.
[rab] It's positively a public service to see that rubbish doesn't reach print. In the past I've rejected several papers for triviality, several for technical slipshoddery, one for outright crackpottery, and one for unwittingly reproducing (but not as well) some of the results from a certain fundamental paper that hardly anyone has read but everyone cites (including the authors of the rejected paper). I assume your refereeing process is anonymous?
Rab] It is not quite the same thing I know, but I dislike interviewing for the same reason. Up to ten people, probably five of which have high hopes for the job have put in a great deal of time and effort to make themselves presentable and revealed a great deal of personal information about themselves are then put on trial for one position. Nine have to be turned down or 'put on file'. I hate it.