Or to put it more domineeringly, even if the Qin family members didn't owe Qin Jiran anything, Su Yanyi still planned to target them, because they had offended her and caused her displeasure!
"It was too obvious what you did, with no attempt to hide it at all." Qin Jiran never doubted Su Yanyi's actions, and any occasional puzzlement or curiosity was very direct. For him, whatever Yanyi said was truth, and he had only just now realized the situation for this very reason. Of course, he believed this was also because Yanyi didn't intend to hide it from him. Otherwise, with Yanyi's means, it would have been easy for her to keep him in the dark.