It wasn't Shang Jianyao who replied to Long Yuehong but Jiang Baimian. "Making friends is indeed more reliable in the short term, but it won't take long for Shang Jianyao's Inference Clowning to lose its effects without the suitable environment.
"Think about it. Most people in the Underground Ark won't help Yu Tian and Bode testify that they are friends with Shang Jianyao. Once they return, they will quickly discover that they were deceived. In contrast, making them misunderstand our identities and think that we are envoys from the Vigilance Church who want to help them overthrow DiMarco's rule is in line with their inner desires. It might even be a manifestation of their hidden desires guided by Inference Clowning.
"People will always believe what they are willing to believe. This way, when they return, they will cooperate with Inference Clowning to deceive themselves, hypnotize themselves, and actively help us do things even if they sense something amiss.