The comment to [this question](https://law.stackexchange.com/questions/79468/can-children-post-images-of-themselves-that-are-not-sexually-explicit-but-provoc) on the screenshot below got promptly deleted.

[![enter image description here](https://i.stack.imgur.com/T68Vd.png)](https://i.stack.imgur.com/T68Vd.png)

What was wrong with it? Which Law.SE term did it violate? If it did, in the opinion of whoever deleted it, contain something prohibited, what was it, how do we define it and what test do we apply to see if the content reaches the threshold?