From the letter, this is why editors are necessary:
After all, we are, as one senior reporter put it, the immune system of this newspaper, the group that protects the institution from profoundly embarrassing errors, not to mention potentially actionable ones.
I believe that all editors should spend a lot more time, all the time, educating the people who make the budgets about why editing is necessary.
I see lots of posts, in various editors' Facebook groups and on editors' email discussion lists, about how we editors should never toot our own horns. Such self-effacing behavior is exactly what gets editorial budgets cut, and I'm not talking about just newspapers' budgets. Yes, of course remember that the author is the one who created the work and the one whose voice should generally not be tampered with, but why hide from the world and never tell anyone about what makes your profession valuable?
By keeping a very low profile, we editors have helped create this problem. Now we must work to resolve it.