That logical inconsistency has been going on for years: With guns, supply (U.S.) creates the demand; yet with drugs, demand (U.S.) creates the supply. The only consistency with that position is, the U.S. is always to blame.
If I'd had my thinking cap on, I could have done better. I'd have asked "If I told you that people in country A are engaging in activity that may encourage people in country B to break the laws of country B, and ask you who's to blame, your answer is going to be 'The Americans'???" Knowing his personality, I think then he'd have seen the contradiction.