Powerhouses may indeed be strong, but that does not mean they should act without restraint, wantonly, and without regard for life. They must maintain a reverence for all beings. They may kill, but they must not kill indiscriminately.
This is the code of the strong, not only an act of mercy towards the weak but also a restriction on their own hearts.
This was precisely why Pei Xuanjing brought forth the proposal to constrain cultivators throughout the world at the Shenxiao Debate Conference, not only for the sake of the common people but also as a warning to cultivators.
And the Qi cultivators of this realm, though powerful, viewed mortals as worthless as chaff; their eventual decline, however, was also the just cycle of Heaven's retribution.
Of course, Pei Xuanjing harbored some dissatisfaction in his heart, yet he continued to read on at the time, wanting to understand the true reason behind it all.