The original report it refers to is from the Software Freedom Law Center and it talks about why free software is more secure and calls for "Software Transparency in Implantable Medical Devices".
Though I may not agree that all open and free software just by that very virtue alone is more secure, I do agree that this area is one that needs the most attention in terms of software quality and security.
The report is definitely worth the read. Even if it doesn't bring about a sea-change in the way we regulate these embedded software, I hope it triggers an internal overhaul in the way medical companies manage their software development process (automated and manual security testing, stringent internal peer review, etc.).