It is very simple.
Any a/v is a major program given system-wide privileges; almost all other programs are limited in their access to Windows files, other program files, user files, etc.,.
Any a/v program must be completely trustworthy and not violate user confidentiality in any way shape or form; enterprise deployment cannot be compromised.
IMO, Qihoo is not trustworthy anymore. And now it is Tencent caught doing the same thing. The fact both were found to provide less protection outside the testing environment is telling. It is not aggressive marketing at all. It is really something else.