Zuo Yan wasn't confined by the City God's Office because she had revealed her true form.
Many things in this world can't be judged by a simple black-and-white standard.
Even with murder, there's a distinction between premeditated murder and self-defense.
Indeed, streaking on the streets in broad daylight is offensive to public morals, but that doesn't mean everyone must wear clothes at home while bathing or sleeping or during intimate moments.
What's the problem with revealing one's true form after midnight? If you don't sleep and stay up all night, even if you don't see a ghost, you're likely to die suddenly from exhaustion.
Moreover, the victims were cultivators of the Longevity Sect—though they claim to be cultivators, neither their identity nor their beliefs have received official recognition, designating them as unregistered and unprotected by human rights.
Unregistered individuals aren't recognized as people and don't enjoy human rights protection.
