Where did you encounter information about the Extrator decreasing the spread of venom via negative pressure? I can't imagine the physics of that ever being effective.

Contrary to your opinion, Sawyer markets its device as a venom extractor: "The Extractor Pump is an easy to use suction pump which can safely and quickly remove significant quantities of venom (poison) or irritants from bites and stings."

Sawyer also claims the device to be scientifically validated:
"The Sawyer Extractor Pump is the only kit proven scientifically to remove significant quantities of venom from Snake Bites. Scientific research also proves the Sawyer Extractor Pump removes poison when treating bee stings. It also removes saliva and anticoagulants from mosquito and tick bites."

I've found no scientfic or medical evidence that the Sawyer Extractor is effective, only reports that are contrary to the Sawyer marketing claims. I intend to contact Sawyer directly form more information.

You're right to suggest that one must be wary of junk science (as the WMS study may be), but to casually disregard scientific and medical research and rely on anectdotal evidence and heresay is contrary to common sense and dangerous.

The WMS notification about the ineffectiveness of the device is here: http://www.wildmedcenter.com/news.html
Further forum conversation that includes citations of the New England Medical Journal are here: http://www.ssnakess.com/forums/general-venomous-forum/63462-snake-bite-extraction.html

I concur with your final assesment; because there are no serious medical consequences to using the Extrator, I too think its worth attempting to use unless or until its been proven to be ineffective and not worth the effort.