Editors are human beings, though you may have been told otherwise, as susceptible to idiosyncratic preferences about language as anyone else. Even the most scrupulous can be tempted to impose a crotchet on a text being edited.
One of mine is to despise the term locals in writing about the members of a community. It is vaguely condescending, the eminent journalist looking from great height at the inhabitants going about their little lives. It echoes the expression local yokels. So I regularly change locals to local residents.
But it is a slippery slope in choosing when to impose a personal preference, and, as usual, it is easier to spot a problem when someone else is doing it. We had a copy editor at The Sun who thought that the word how should not precede a clause. He would routinely change "how the copy editor approaches the text" to "the way the copy editor approaches the text." Where he got this notion I cannot say; it does not come up in any of the manuals I have consulted, nor does it achieve a significant gain in clarity.
This is dangerous, principally because editors tend to find what they are looking for. If you have a set of arbitrary preferences in your head, you will find all that occur, at the hazard of missing something important. I wrote the other day about copy desk busywork, and the unreflective imposition of personal preferences is another example of time-wasting edits.
So I try to examine my own preferences, consult with linguists, lexicographers, and usage experts to see whether there is justification. In the case of locals, I can explain my reasoning if challenged by the writer or another editor. In other cases, I can appeal to authority, such as Theodore Bernstein's Miss Thistlebottom's Hobgoblins or Garner's Modern English Usage.
You do not have enough time in editing to do everything that you need to do, much less everything that you would like to do. You need to examine very carefully how you are spending that time.
