Someone wondered how the misidentification of passive voice started, this was my answer:
My guess is at some point someone said, "Hey, a lot of your sentences are passive, for fiction you should use more active sentences."
And they were like, "Passive?"
"You know instead of She was bitten by the dog say The dog bit her."
And they saw the lack of "was" as the difference between those two sentences and went forth to spread the word that "was" is evil.
So armed with this new found knowledge, these internet warriors scratched out sentences like "She was running out of time" and replaced them with "She ran out of time" because it's more "active" ignoring it no longer makes sense. Or if they realize it doesn't make sense, something super awkward like "She began to run out of time."
As people killed off the wases ruining their great literature, they realized right next to them were -ing words. Those were also removed when the sentence was fixed, so clearly those were bad too.
Then someone somewhere saw verbs with -ing were gerunds and therefore their foe had a name! (even though it's only a gerund when being used as a noun so actually applies to zero percent of the cases they are against)So they decided, in the name of good literature, the gerunds and the wases must be destroyed!
And then self-publishing got big and people needed platforms. But other people didn't care what they had to say...unless they were teaching writing. So taking their shoddy knowledge, they made blog posts, which they later turned into e-books. And the grossly incorrect fallacies spread. And now they had authority! It's in a book! It's on a website! It must be true!
Sure they could have been spending that time learning about story structure and characterization, but that shit's hard. Easier to do a "find all -ly" in Word.