I write about this. It's both something commonly done by some parents and something I've always had an inexplicable - perhaps now a bit more explicable - extreme aversion to.
I found out recently - from my 'father', no less, and quite explicitly - that, quite apparently, I was sleep-trained.
Well, what he actually said was, and I quote:
NF: "She (me) should just throw her (my teething toddler) into the room and close the door."
NF's GF: "But she'd just cry more, wouldn't she?"
NF: "Sure, until she passed out from crying. I put [Pronoia] to bed at 7PM and she woke up at 7AM, and wouldn't bother us then, either. It's all a matter of training (in my language, the word he used can only be applied to animals, and even then it's condescending), ha ha ha."
Before this, he "jokingly" suggested that I throw the crying toddler out the window, before which he "astutely" observed she was "only after being the center of attention" (projecting much? she actually cried more when people tried to cheer her up) and after which he cheerfully said towards the other present children: "We'll just pay attention to the good children here (the crying teething toddler is not "good")."
All this made my physically sick. I said nothing, though, except "all the children here are good," because:
a) I don't want to ever censor him. His stupid outbursts provide the only information I have about my childhood. If I react to something negatively, he'll lie about it in the future.
b) other people were there, including my ILs. Above anything else, they desire a good relationship with their son's FIL (these things are close and important in my culture).
My FIL, for that matter, chose to share a story from his youth - a story that obviously troubled and bothered him. He remembered the time when his friend, 14 at the time, was severely whipped by his father right in front of him. He carried welts on his back for a month after that, my father-in-law related, concerned and confused. What did my 'father' do in response?
Can you guess?
That's right. He laughed.
Because there's nothing funnier for malignant narcissists than hearing of others subdued, hurt and humiliated.
This is the man who 'fathered' me.
Of all the things, I have been grieving about the sleep training the most. I can feel it. I could feel it with my babies. When I put one of them to bed and just went to pee and she woke up and I couldn't come get her immediately - once - once - I felt like the world would come crumbling down. My baby needed me and I wasn't there. She trusted me to be near her and I failed her. It was a hell of horror that I'm sure other mothers haven't really experienced. If they hadn't been sleep-trained, that is.
I can't say against so many voices out there that this is objectively evil. But I feel it in my bones and call "abuse" on it! And them!