Why legal protection for technical measures is controversial

On August 14'th I gave a presentation on legal protection for technological measures, and why this policy doesn't fit well within Copyright law (Slides, link to audio recording)

Summary: The types of activities which copyright regulates all assume that you already have access to content. Copyright never concerned itself with concept of access, which was left to other laws.

Technical measures can restrict access, but can't in the real world directly restrict the types of activities that copyright regulates.

Copyright and technical measures are disjoint, but technical measures and other areas of law such as contract and e-commerce overlap.

Is technology useful for stopping an authorized person from doing things which Copyright regulates? Should we radically change "Copyright" to address this problem, or is this a non-Copyright issue?