Is bad, to be clear.
If you want a stage 3/4 stance on this, I take the stance that it is bad to beat the developmental levels out of children.
But, speculating here... maybe it happens? A lot?
When thinking about my own journey through the developmental stages, I realize that I mostly "skipped" stage 3 by the normal descriptions and was doing clear stage 4 moves even in elementary school. They weren't very sophisticated moves though. It's not like "Yeah! I'm so advanced I was learning relativity in elementary school!" or anything. Exactly the opposite, actually. One of the earlier examples that comes to mind is failing to learn relativity in elementary school. I asked my dad why E = MC², and told him "Okay, makes sense" because each baby step in isolation did — or at least, seemed to at the time — but when he got to "therefore E = MC²" I had no understanding of the broader arc he was trying to take through, so my response was "Wait, why does E = MC²?" which frustrated him.
So the "developmentally advanced stage 4 move", not subject to relationships but a larger system that can take these as objects... was "Wtf dude? I'm in elementary school, what do you expect?". It's not complicated. Maybe hard, for most people, in many contexts, but this wasn't a context that made it hard.
If my dad had been abusive, or even a tiny step down that spectrum, then hell yeah it would have been hard to take attitude towards him like that, and I probably wouldn't have. I'd rather avoid getting beat slightly disapproved of. Who wouldn't?
But the reality is that he was gonna say "Yeah, you're right", because duh. The relationship was just secure, in reality, and obviously so therefore also in perception. And so developing very basic stage 4 thoughts is easy. Doesn't have to hold up to serious social pressure. If rejecting social pressure never gets safer than "My girlfriend might dump me", then yeah no shit it's gonna take until adulthood and maybe not even then.
Watching my daughter develop brings to mind very similar thoughts. Wanting to bring Dad breakfast and be appreciated for how she's growing up to be a sweet and empathetic kid doesn't sound complicated. Neither does "Eh, maybe I don't wanna do that today". But if I were to push her that she has to be nice... and obviously there's much gradient to do that, because who wants their kid to be a little shit head? Well... that can be fun too, I guess, but only if you stop to think to ask for it.
If I were to pressure her to be nice — like the wonderful threetards at her school do, because they were developmentally stunted at the same age — then how can I expect a six year old to push back and say "No, actually I just came up with a system that is stronger than you Dad". Of course it's gonna take a while. And if I were to not stop and appreciate the frozen burrito she microwaved for me because "it's just easier for me to do it myself", then how is she going to learn the value of taking self interest as object?
Higher levels in others can be inconvenient. Fives will break fours, and fours don't like this. Fours will break threes, and threes don't like this. Well, threes will break threes too, but fours will do it remaining stable and feeling righteous, which kinda twists the shiv a bit. It's easier to manipulate a two by dangling candy than it is a three who feels condescended to. Even harder to manipulate a four who can't be guilted into it because "Bro, I understand Shapley value".
And like, it's not just abusive or lazy parents. Good luck having a kid and not telling her "Dude, I'm busy. Go away" now and then. And what do you think happens to her desire to bring you breakfast if that's how you're gonna respond?
Maybe the reason developmental levels are reached so late, if at all, is because we're all crabs in the damn bucket trying to make sure people don't develop too much out of sync with us. Maybe they show up late because they show up when stage transformation is required. Maybe that's why Chapman's stories of catalyzed stage transformations are so traumatic and involving threats of suicide/homicide/losing jobs/etc. Maybe we're seeing them when it's time to sink or swim, rather than when it's first available, to those supported in finding them.
On the other hand, good luck raising your kid ready to handle the outside world if you don't push them away when cognitively strained.
Carrying yourself in a way you can stand behind, when strained, in a world where she'll have to learn to deal with strained people, and then repairing the relationship when you deliberately or otherwise regress to stage 2 to tell her to "Go away", is a stage 4 move. Because regressing to stage 2 is a stage 3 failure, and requires taking one's relationships as objects.
This one, however, is complicated.