I think the MSVR and the SWIAT (Secure Windows Initiative Attack Team) are separate entities with separate missions. The SWIAT (which may have a different name now) guys focus on attacks on Windows and other MSFT products, and the MSVR is looking for vulnerabilities in 3rd party software. But I doubt the MSVR's reason for being is to discredit those vendors. MSFT has spent the last 10 years on the other end of that equation and I'd guess their main interest is in making the software that runs on Windows machines safer, because they know that Windows users tend to put all of the blame for security problems on MSFT, regardless of which software has the problem.