While not strictly illegal, watching or creating media that centers around human relationships is considered extremely "distasteful" in demonic society.
Although the initial stages of a human relationship dynamic can be similar to that of demon courtship, it very quickly progresses to unsavory places, ESPECIALLY when it comes to the creation of a "family". The concept of parenthood is non-existent in Demon society, and even the idea of individual demons creating and then raising a demon that they are the sole caretakers of would strike almost any demon as perverse and unsettling.
Still, there is an underground market for such media, and occasionally the Masters need to step in and chastise demons who become too curious about wanting such liberties for themselves.
-Notes on modern demon society by Demon Master Dzu