Put that scam aspect together with the fact that there weren't other legitimate editing or publishing options years ago and the advice to not pay for editing before submitting made sense. (jamigold.com)
I know of a number of traditionally published, very successful authors who pay for editing before it goes to the publisher because they don't trust their editors any longer. (madgeniusclub.com)
One of the downsides to self - publishing is that often you have to pay for editing services out of your own pocket. (toughnickel.com)