Now, anyone with clear eyes could see through it:
The reason Tie Taihe, the Left Protector of the Taiyi Immortal Sect, had Duan Lingtian state his intention to join the Taiyi Immortal Sect before killing Teng Qing, the elder of the Longwu Immortal Sect, and Xue Lang, the protector of the Thousand Spiders Immortal Sect, was purely to establish a justified stance—to have a legitimate excuse to kill Teng Qing and Xue Lang.
Huang Chao was a man of the Taiyi Immortal Sect, so Tie Taihe could have killed him without any excuse. Even if the sect master of the Taiyi Immortal Sect were present, he would at most utter a couple of light reprimands and not pursue the matter deeply.
Chapter 2778