I just now rejected three articles for three separate prestigious journals (these seem to come in batches). I have a dissertation to read and a Graduate Student Doctoral Exam paper. This summer I have at least one tenure review to do. In short, I am a gate-keeper, one who is paid (well, usually not even paid) to say whether someone should pass an exam, get an article or book published, get tenure.
There are two ethical issues involved. One is to perform these duties fairly and conscientiously, to disqualify oneself when there is a conflict of interest or a breach of confidentiality, to put aside one's own stake in a particular debate in the interest of disinterest. This involves a narrow adherence to the ethical code of the profession.
The second issue is whether the process of gatekeeping itself furthers a larger aim. I want to promote the kind of work I think is truly valuable and help other people have successful careers like I have. There is no issue when the work is strong; even strong work that goes against my particular point of view is valuable in the larger scheme of things. Having to reject work, however, does me no good psychically. In most cases, the rejection is justified both on narrow grounds (the academic code) and in terms of my larger aim of not wanting to be embarrassed for my field. I like being a gate-keeper, but I like having a positive benefit. I can point to an issue of a journal and say, "I helped this author improve his or her article and get it publlshed." That's wonderful. But I wouldn't point to the same journal and proudly proclaim: "You see this issue, I kept three bad articles out of it."
Yet the bad articles do have to be kept out.