RSA, Security - RSA: Symantec's Thompson Swipes at Microsoft - CRN

Because somehow Microsoft has an incentive to cheat on security?  I don't see how this analogy fits.  Should I stop trusting my car manufacturer to include robust safety systems as well? 

In his next breath, Thompson took a thinly veiled swipe at Microsoft for creating what he characterized as a "conflict of interest."

"Who would trust one company to do everything for them? You wouldn't want the company that is keeping your books to audit them," Thompson said. "By the same logic, you wouldn't want the company that created your company's operating platform to be the one that secures it. It's a huge conflict of interest."

Source: RSA, Security - RSA: Symantec's Thompson Swipes at Microsoft - CRN