For whomerer doesn't oppose SW patents, here's a very well thought writing by Phil Salin, which equates patents to censorship of free speach:

Imagine if, for 17 years, only one author was allowed to write about the plot line "boy meets girl, boy loses girl, boy regains girl". Or that once some consortium of artists has invented rock and roll or string quartets (and produced an initial "reduction to practice"), no one else could write music in those styles for 17 years without their permission. Or that once the first mathematician has invented a technique for dividing numbers, all other mathematicians must for 17 years request permission before inventing their own techniques, for fear of accidentally reinventing or coming too close to reinventing what another mathematician has also thought about. In each of these cases, imagine the arrogance of someone claiming a right to bring before a court of law and convict of a civil crime all others who choose to think for themselves and write independently. [Phil Salin]