From Wikipedia:
>"It is based on the idea that there are no bad children, just good and bad behaviors."
Given the fact that we've known for decades now that behaviour is roughly 50% nature (and 50% nurture), this foundational (implied) premise is unequivocally and demonstrably incorrect. Some children are "bad" and need to be taught not to hurt others. This parenting style is growing in popularity and I don't think it's a surprise that we now see an epidemic of kids with mental health problems.
I recommend listening to this lecture from Jonathan Haidt: https://www.youtube.com/watch?v=B5IGyHNvr7E&t=569s
Children certainly need boundaries and rules. They need corrective measures when children rebel. I think it's clear that a lack of negative punishment is leading to all kinds of negative outcomes for children.