You can't see how it's complicated? Not at all? No historical events pop out as "it's not normal precedence to arrest people in other countries for crimes in your country"?
I mean look at the international outrage when people from country A commit a crime INSIDE country B and country B punishes based on their own laws. The north Korea prisoner who was tortured and died shortly after release stands out, but there are plenty of other examples.
To just say "I don't see how anyone has a problem with this" makes you sound like a shill or someone trying to look enlightened, because it's not hard at all to see how this is complicated.