Because he's a weird insecure psychopathic man-child.
Don't give him enough gratitude? Eternal suffering. Break one of the weird rules he apparently really cares about (but then allows his most trusted disciples to break)? Eternal suffering. Succumb to the biological drivers that are inherently within us? Yep, more eternal suffering.
Don't give him enough gratitude? Eternal suffering. Break one of the weird rules he apparently really cares about (but then allows his most trusted disciples to break)? Eternal suffering. Succumb to the biological drivers that are inherently within us? Yep, more eternal suffering.
I would say you can't make this stuff up, but...