The problem was that some of the files Megaupload held were reportedly illegal but the company allegedly refused to get rid of them.
Mr Kumar said people who chose to download files more slowly could do it free but people who wanted quick or multiple downloads paid a subscription fee for the service, as little as $10 a month.
Asked what kind of people wanted the "quick and easy" service, he said: "Every teenager in the world."
Many people use file-sharing services legally, such as businesses which want to share a video or large file with clients.
The illegality comes when people knowingly possess, or allow the sharing of files they do not have copyright for.
Mr Kumar said shutting down Megaupload was not entirely unexpected, but the court action would not stop the sharing of files over the internet.
He said Megaupload would leave a vacuum but other sites would appear and the battle between copyright holders and people wanting quick and easy access to movies and games would continue.
Kiwis in particular downloaded copyrighted materials because "Hollywood has made up its mind to give it to us six months or two years late. It isn't available to us quickly, legally or at an economic cost".
"Most teenagers in New Zealand have heard of Megaupload, even though older people haven't, that's where they get their TV shows and movies from," Mr Kumar said.
"I know several teenagers are moaning and groaning about their usual place not working, but just like they found this place in the first place [they] are going to find others very quickly, which is the point - unless you fix the issue, in the long run all this stuff isn't going to make much difference."
File-sharing
* The sharing of computer files, sometimes on physical media such as CDs, but mostly conducted anonymously across the internet. Such files can be video or music. Megaupload was a "cyberlocker", which stored complete files and provided its users links for their download.
* Other methods of file-sharing include the "BitTorrent" protocol, which aggregates sections of a file from multiple sources, allowing websites to advertise how they can be obtained without having to physically store a complete copy.