I'm not denying that MegaUpload engaged in piracy, but that doesn't stop it from ALSO being a general-purpose file host.
This is very tangential to copyright law, but there was no good reason morally (and, as far as I'm aware, legally) not to return customers data.
Correct, and this is why Amazon S3 probably the biggest filesharing system in existence is not being sued and being taken offline. Megaupload, not so much.