Everyone's typing posts in here, or touching the screen of some techy-touchy device. (Exceptions not included; the point is, no one's writing) So, we can get typos.
Imagine a situation where a good question is being asked, and a better answer is being given. You start reading the answer, and suddenly see something like:
They are the responsible compounds for the bad smell of water, and hey are what we've been trying to get rid of.
[This is just an example]
There's that "hey" which should be "they" and is raising its ugly head in there!
What should an editor do about it? Edits are supposed to be substantial, and in contrast, that little error is still there. I just got to a 1000 rep (WHOOHOOO) and I'm set to do a heavy job of editing, but this should be solved first.
Hey, if you want to say that such a thing doesn't happen, I've seen the case and am asking for it now.