You carried artifact which is illegal so I demanded that you drop it. Fine came after you tried to bribe me.
Beside fine for illegal cargo, another part of Kusari Legal Codex says:
Quote: Defaming the State or the Emperor or insulting a Samurai's honor (all KSP/KNF officers) is forbidden and fined or paid in blood.
Fine: 2M
Also, your tone in conversation didnt help either.