Well You are approching what USED to be called conservatism and what approches a libertarian mindset
If Liberty is the goal of society
and All Laws, by nature, restrict Liberty
however
Laws are often required to prevent 1 party from infringing on the Liberty of another
then
Laws should be limited to those that are absolutly nessicary.
Keep in mind, that the ability to profit from one's own work IS part of Liberty
However, The right to do what you please with what you have purchased is also Liberty
You have the Protection vs Fair Use debate.
Now, as to the specific issue, I believe that there are a number of legitamate uses for File sharing software
Back when the Video Caset Recorder was first released, Sony tried to sue BetaMax because people could use the VCR to infring copywright. They could, for example, record an NFL Game and then charge admission for it to be watched.
That case was decided in favor of BetaMax because VCRs had the legitamate use of "Time Shifting" (Watching a program at a time other than when it aired)
This set a legal presedent (sp) that Legitimate use of a technology TRUMPS Possible infringement using a technology
This has been clouded and confused by industry pundits and Lawyers lately who know they are dealing with an older and somewhat non-techsavy Judiciary.
Fortunatly there are organisations like the EFF
www.eff.org that attempt to educate the Lawmakers and Judiciary while offering pro-bono representation to citizens who come under the heal of industry lawyers in the technical field. (They got their start representing hackers)