This is absolutely not an editors job--and you've just managed to piss off a lot of editors all at once.
No, I've (apparently) only managed to upset a few people such as yourself.
It's not even hard to find online sources where authors, agents and editors talk about how the editors proof-read their manuscripts, pointed out errors and also suggested significant plot changes. If I remember correctly, Stephen King's book
On Writing has a chapter devoted to how a newspaper editor taught him how to edit by editing his articles.
It is universally agreed that editors point out errors and yet you're actually trying to say an editors job isn't to find them? We are defensive, aren't we? To the point we're claiming although employed to find errors it's not the job to find errors?
You can throw out as many excuses as you like for why an editor didn't catch something; a book that goes to print from a large company has been read by dozens of people and if simple errors make it into the final product, the fault lies with the one who wrote it (the authors) and those who are employed to catch the errors the author didn't notice (the editors).
I'm also fairly certain that, unless publishers are no longer operating as a business, there is a clause in a publishing contract which stipulates the publisher reserves the right to make changes to the manuscript to ensure it is "fit for publication"; or something along those lines.
You know what the most tragic thing is? If there are editors running around thinking their job has nothing to do with quality control, that may very well be a contributing factor to why many books never earn back their advances. When I see threads like this that talk about the errors in books, as a reader I'm a lot less likely to look at other books printed by that publisher. A book does not just represent the author; it also represents the publisher. This is even more true for small presses; I've been looking at a lot of them lately and I check out what find of reviews their books have received. I won't even submit to the ones where the reviews have pointed out a bunch of errors.
But it is solely the writer's fault. By the very definition of the word "writer", your job is to get things right.
The definition of the word "write" has nothing to do with being "right". They are different words.
When you try to prove a logical argument is false, you have to actually use logic.
The biggest problem you have with my post is something my post doesn't even say. Somehow you interpreted my post as, "authors have no blame" into "editors take all the blame". My post actually said, "Editors and authors share blame".
The publishing of a book is a collaborative effort. I am not the one dumping the blame for a collaborative effort onto one individual. That is what your posts are doing.