Process arguments aside (and there may be process arguments that demolish the US case here, and I care about process too, especially if they involve getting evidence in bogus ways):

The US has Kim Schmitz dead to rights in this case.

There's a whole mythology about what MegaUpload actually was, and it gets partial anecdotal support from people who, for instance, used it or had friends who used it solely as a sort of Dropbox or benign file transmission method.

But when the DOJ imaged the servers, they got Schmitz's mail spools, and they have Schmitz and his employees in black- and- white discussing payment systems that disbursed cash to users specifically based on pirated media.

My favorite anecdote from the indictment:

At one point during the operation of MegaUpload, a user downloaded an episode of Dexter from it, and complained to Schmitz via email that the video quality was low.

Schmitz responded not by scrubbing Dexter off his site, but instead by demanding that his staff fix the video quality issues.