Chen Yang isn't a fool; he fears the terrifying penalties imposed by Right Hand, but that doesn't mean he would naively believe Right Hand's explanation.
Regarding the four modular form issues raised by Right Hand, he is skeptical, and retains a reserved attitude in face of things he dares not wholly deny.
However, since being infested with Right Hand, his personal stance has undergone a significant shift. If he had encountered an extraterrestrial civilization before, he would certainly align himself with mankind. But now, after being parasitized, he doesn't control his life or death. To avoid excruciating pain, to survive, Chen Yang has no choice but to follow Right Hand's every command.
At least for now, without understanding the specifics of the Right Hand and its weaknesses, Chen Yang absolutely needs to obey, to be an honest "friendly" Earthling.
