So pekelo are you for strong and effective regulations to keep crooks away or are you for NO regulations ( irrespective of which country)
How about in between? Just because the mighty US can force other countries to help them out, that doesn't mean it always should. Also, if the crime is more or less victimless (Sarao's definitely was) and it isn't even a crime in that country, they shouldn't be extradited. If the criminal is a murderer, sure, go and get him.
Speaking of murderer, there was a case where an American murdered a fellow American in Australia. He got jail term there, then when he came back to the US he got arrested again. It sounds to me he was prosecuted twice for the same crime...
Just to underline my point, let's look an opposite case: Let's say a Putin critic is wanted in Russia because he criticized the dear leader, what happens to be against the law there. (let's assume) Should the US extradite this person just because he committed a crime in Russia, although that isn't a crime in the US? Although this is clearly a political case, you get my point...
Now Sarao's case is different from Kim's because when you become a trader you agree that you will follow certain rules and regulations, one of them outlawing spoofing.