Compared to the monsters, mankind was an emergent race who managed to defeat previous rulers.
In earlier stages, monsters held advantages that mankind could hardly match. Monsters were physically strong, violent in nature, and possessed innate divine abilities through their bloodline, which required no understanding to manipulate freely.
In earlier stages, humans were physically weak. Before learning Taoism and divine skills, they should read enlightenment books like "Introduction to Cultivation", memorize the path of spiritual energy circulation taught by the school teacher, numerous times, and then awaits the intake of the spiritual energy into their bodies, after which they could learn some shallow Taoist techniques.
Taoism was not something that could be mastered instantly. It required comprehension and talent. Even at the Foundation Establishment Stage, not all would grasp the basics of Taoist techniques.