If we’re really gonna get into any hypotheticals of what Shen Jiu’s response would have been to Yue Qingyuan admitting why he didn’t rescue the former, then let’s not forget that the only scenario in which Shen Jiu can see himself forgiving Yue Qingyuan’s “failure” is if Yue Qingyuan dies in the attempt. This is, of course, referring to the whole Bingge ambush thing, but this also refers to how before Shen Jiu reunited with first disciple Yue Qingyuan, he was comforting himself with the thought that the reason Yue Qingyuan never returned was because he had died. She Jiu was literally imagining holding a little funeral for him, because in his mind, Yue Qingyuan is useless without him. The fact that Yue Qingyuan not only survived on his own but ended up living the dream that Shen Jiu wanted (again, in his mind since we know that yqy was not living “the dream”)? That was what had Shen Jiu pissed.