blame
訽 centers on expressing strong disapproval through words: blaming, scolding, or shaming someone verbally.
訽 combines 言 (speech) with 句, which likely contributes the sound. The exact historical development of 句 as a phonetic component here is uncertain.
Words 言 shaped like a hook 句: imagine sharp, curved words that catch and pull someone down, blaming and shaming them.
For コウ, picture a public announcement (公, コウ) of blame: the official 公 reading cues コウ, and the words 言 deliver the public shaming.