Did you just assume that Etherium is American?
Also, for reference I'm not American.
Of course Washington doesn't want to give the Russian, Chinese, and Indian establishments common cause against the US.
What happened to Dotcom is fairly normal in the case where someone in country X is doing something that violates similar laws in both country X and country Y, more of the damages are occurring in country Y than in country X, and X and Y have extradition treaties.