Why retract a paper for intellectual property protection?
My answer is based on an understanding of UK patent law. The UK Patents Act 1977 is based on a "first-to-file" patent system. This means, in part, that an application for a patent may only be validly made if that invention was not part of the state-of-the-art at the time of filing. State-of-the-art includes any information made available to the public as of the priority date of the application, which is usually the date of filing. 

If confidential information regarding an invention is made available to the public without the consent of the inventor, before a patent for the application is filed for it, then under UK law the inventor may still make an application for a patent without the prior disclosure - the unauthorised release of confidential information - rendering the application invalid for lack of novelty.

In this case, if the journal published the confidential information before the inventors/authors authorised the release of the information - presumably before a patent was filed for the subject matter of the paper - then the retraction of the paper may indicate that the journal is acknowledging that they released the information inproperly, i.e. before an agreed embargo date set by the authors. This may add weight to the inventors' argument that the prior release of the confidential information was made without the consent of the authors and that the authors, as inventors, may still validly apply for a patent.

I am not a patent lawyer. This is not patent advice. My comment is written from a UK patent law perspective.