If humanity had not created these substitute lives, if it weren't for humanity's own folly and arrogance summoning the Evil God, this world would never have fallen to such a state. To simply blame it all on them—that is something Malin cannot do.
If they must truly be eradicated, Malin would not hesitate or feel regret over the slaughter of so many lives. But Malin would make this decision based on the right to survival, using the aphorism "One cannot allow others to snore beside one's bed" as a guiding principle for their Fate, rather than hypocritically claiming it was their actions that dragged human civilization into the abyss, and then using such a baseless reason to justify their cleansing.
Because to act this way is to insult humanity itself. We humans do not need such hypocrisy.