Ok, with this translation i got to understand this chapter, it wasn't so hard but the translation of the other group confusing.
So they rely on the humanity will give up on their emotions with time. Well, it is a typical one and many comics set in the far future or with aliens and movies use it but not common enough to not be interesting. The fact that it is something that have been told by psycologists over and over gives it a realistic feeling at least.
What does not make sense is the people (Gengo and Scarlet) desparing over this truth, it is not THAT bad ...