Any pipe to the US would have challenges on the northern end as well. The connection has to connect to something, after all, and the US government could just as easily apply pressure at the point of presence to any backbone provider who peers with "MegaPipe".

It seems like the idea here is to prevent Mega's "legally challenged" (as another commenter put it) servers from being disconnected by going all the way up the 'chain of command' and creating his own backbone. He intends to give the backbone legitimacy (to forestall any funny business at the PoP) by providing free internet to New Zealanders, thus generating large amounts of 'legitimate' traffic on the link.

Edit: Just to be clear, like rdl, I don't actually think this is a worthwhile thing to do.