Certainly, they also believe that copyright and patent law needs to fundamentally change.
And certainly, preserving the right to privacy on the internet — to the same standard that it is guaranteed through other means of communications — would make it pretty much impossible to shut down piracy. But that's a side-effect, not the expressed goal of the party.
I'm Swedish myself, I've studied their platform closely, and I voted for them. Not because I want free stuff — but because I feel that the EU parliament needs more people in it who are viciously opposed to the idea of destroying our basic civil liberties.
Many other candidates from other parties are sympathetic to this (as opposed to their respective party platforms). But — only a vote for the Pirate Party would shake the "old parties" up sufficiently in order to make personal integrity the party platform. And I think we're going to see exactly that kind of progression in Sweden across party lines.