I guess the main message this is trying to convey is something like JJK's circle of violence.
First Soyo's bullying "kills" Lally (I know thats now the case but I'm trying to explain what the author is going for)
Lilly hates humans because of this and kills Soyo, becoming a murder
Then Kitami hates aliens because of this and kills a buncha aliens, becoming a serial killer
Then Lilly sees this and escalates killing all the humans in the idol concert, kidnapping the idol and probably torturing and killing her
And now it's up to Kitami to either continue or end the circle of violence.
Then again aliens wouldn't have been hated had them not emigrated into earth in mass, accepted all those benefits at the expense of humans, caused havoc on human culture etc. Probably caused the grape, loitering, theft and violent crimes rates to skyrocket, lived a comfortable life subsidized by the human tax payers who suffer their violence and who are ignored by the authorities giving the aliens a free pass to do whatever, etc.
So I'm not feeling a lot of sympathy for Lilly and Lally but I think I understand what the author is trying to convey. I have to say this manga really raised its quality these past few chapters. The art, paneling, everything is top notch