Most of Schneiers criticism actually relates to the sloth they exhibited in adding detection once the threat was exposed, and the fact that they tended just to remove the rootkit, not the unstable DRM components.
There are numerous difficult questions in this scenario. Its easy and cheap to lash out at various industries for not doing better for consumers, but many of the things Schneier and his blog comment writers yell about just couldnt be helped.
The fact remains, and will continue to remain after this, that its not always easy to determine what is a threat and what is legitimate system software performing privileged operations. For instance, FORMAT.EXE can destroy your hard disk, but its not malware. How should an anti-virus program know the difference? The more important fact is that in this case two companies that should be trustworthy, Sony and First 4 Internet, betrayed that trust. This is enough to make a mess of any reasonable security system.
Incidentally, I may as well point out here that a great way to protect yourself against the First 4 Internet rootkit and many other threats is to disable Autoplay, the Windows feature that automatically runs software when a mass storage volume is attached to the system. Its most famous for CDs, but works for all media—USB keys, for example. Click here to read how to disable it for all drives on the system.
I was recently on a security discussion group with the great Dr. Solomon (author of a famous anti-virus product later bought by McAfee). The good doctor posed the (rhetorical, of course) question of why the Sony rootkit is something that an anti-virus product should detect. The main answer, and the reason its a threat, is not that it performs DRM functions but that it hides itself sloppily, opening up the system for exploitation by third parties. (Dr. Solomon still has lots of friends, but no financial interest, in the anti-virus industry.)
If this is true, the doctor continues, surely an old, unpatched copy of Internet Explorer qualifies as a threat to be flagged by anti-virus software. After all, it has vulnerabilities that are being actively exploited in the wild.