The negotiation expert's words had no issues.
The words of Ant-Man also had no issues.
Why did their words all sound reasonable, and each one more so than the last?
Because many things in this world don't have a unified standard.
Especially after factoring in perspectives!
Regarding the same issue, the same choice, people with different perspectives might have different attitudes, different judgments.
This logic based on individual perspectives was 'correct,' at least to the people making those logical judgments.
The negotiation expert's logic was based on a simple sense of justice: He's just a child, why would you want to hurt a child?
Striking at the weaker, who lack the ability to resist, is undoubtedly unjust.
From these viewpoints, his words indeed matched the simple sense of justice.
But the kidnapper wearing the Ant-Man mask held a more realistic view of justice.