1. There is no national debate over intelligent design
2. The movie is not an educational film and certainly does not provide a scientific examination of the theory
3. It cannot present such examination since there is no theory of intelligent design other than appeal to ignorance.
4. PBS has no requirements to teach religiously motivated arguments camouflaged as science
For a better understanding of the Discovery Institute's religious and political motivations please read the Wedge Strategy.
For a better understanding of why Intelligent Design fails as a science read the following resource:
Why Intelligent Design fails