Megaupload was not just being used from the U.S., but it had servers in Virginia, was actively targeting U.S. customers, and dealt largely in the infringement of U.S. copyrights.
If a foreign citizen commits a crime in the U.S., does the U.S. not have the ability to prosecute him just because he's not a U.S. citizen (= "registered as a company in the U.S.")?
> If a foreign citizen commits a crime in the U.S., does the U.S. not have the ability to prosecute him just because he's not a U.S. citizen
If a foreign citizen commits a crime in a foreign country, the US can still prosecute him (and can even have him forcibly abducted outside of the existing extradition treaty of his country, violating the laws of that country, to bring him to court without reducing its ability to prosecute him.)