After the Nirvana Plan was executed, the doors to Earth civilization swung wide open.
One could come and go... and if truly wished to leave, the threshold would become very low.
The atrocities of the Blood-crow were extremely heinous in themselves, but what was even more unacceptable and even hated, was that they, unable to adapt to the new environment, had the choice to leave.
"Why must they first commit a massacre before leaving? Isn't using the blood of other species as a sacrifice acceptable?"
Although politically incorrect, this view was widespread among high-order professionals.
What angered them the most wasn't the act of "sacrifice" itself, but rather that, when there were better options available (although at a higher cost), they still chose to harm their own people... this made many feel uneasy.
Yes, that was the key issue—professionals were still human, ordinary humans with families, mouths to feed, careers, and social connections.
