When, like Dotcom, you instead actively solicit pirated material, optimize the pirated material on your site for quality, and pay users to put more pirated material on your site using a sliding scale based essentially on how pirated the material is, the DOJ reasonably concludes that you are not a public video site like Youtube, but rather a criminal conspiracy.
Dotcom appeared to have been operating under the misconception that a "notice and takedown" system insulated him from that charge. Dotcom didn't actually read the DMCA, because notice and takedown is only ~half of the responsibility of an online service. The other half, written right into the DMCA, is operating without red flag knowledge of pirated content.