They were robbed once，why YOU try to rob them twice!

这话你应该对那些被骗作小白鼠的患者和肖师傅讲。They （患者）were robbed （被病魔）once：那些患者已经被病魔折腾得很痛苦了
why YOU （肖师傅）try to rob them twice!：为什么肖师傅你还要再骗患者一次？