If you read all the research and citations listed on the site, you will see exactly how and why they are providing this service. They also have an excellently researched and well received book available explaining exactly how to 'reverse' diabetes (I have had it listed in my forum signature for the past 4 years). In essence, it tells you how to low carb properly. Virta seems to be a way to help people do this with appropriate online support and coaching from qualified medical professionals.
Voleck and Phinney (founding members of Virta) have been working in research for decades. They have run studies, present at conferences, write books, publish research, and are now trying to reach an even wider audience.
Nothing is free. Here in the UK we pay National Insurance and fund the NHS. Over in America, they pay insurance individually, and then additional fees as and when needed.
Since Virta is providing an integrated service coordinated with the patient's own doctor, this is a VERY different proposition from the usual snake oil miracle cures that pop up all over the internet.