This would indeed result in no more war, at all. I fail to see the problem. (Besides that it wouldn’t work, of course – but it’s a nice fantasy.)

The CNN article says that he was selling horns to people in Manhattan. Jurisdiction for international crimes is complicated and I don’t know anything about it really, but my guess is that even if he never personally visited the States, he’s still considered to have committed crimes there – if a drug smuggler used a catapult to launch packages of drugs across the border, it would make sense for them to be charged in the US even if they didn’t ever step foot on American soil.