As I am a inventor (unsuccessful commercially) I remember being nervous about this policy when it came out years ago, and speaking against it. The rationale sets individual interests against common interest. I am sure that corporations do exploit copyright and patents, but individual inventors and creatives need encouragement. The policy seem insufficiently thought through to me.
As ever, there are two sources to be considered : our massive, 300+ page Policies for Sustainable Society (see 3.1.3 here) being a record of all policy decisions taken at Conference since the 1970s (updated occasionally), and our present Manifesto for the 2015 election (see p61).
The writer of the 2015 manifesto is going to refine the policy at the next Conference. Clearly we need to act to protect the livelihoods of our creatives.
Update: Caroline Lucas clarifies the position. http://www.carolinelucas.com/latest/copyright-standing-up-for-brightons-creative-industries-artists-and-writers