Gawker has an email exchange between Ryan Tate and Apple head honcho Steve Jobs that's partially about the technical/business issue of why Flash won't be allowed on the iPad, but also about the issue of porn on the net.
Yep, freedom from programs that steal your private data. Freedom from programs that trash your battery. Freedom from porn. Yep, freedom.
And you might care more about porn when you have kids...
Aha, I thought, here's the nub of it. Jobs employs the old "won't somebody think of the children" canard, situating the iPad in a purely domestic environment where children are central, and nothing that could potentially or purportedly harm them must be allowed it. As Walter Kendricks pointed out in The Secret Museum, censorship requires the idea of the "vulnerable person" who must be protected from the influence of pornography.
From a strictly business point of view, this attitude may hamstring the Apple iEcosystem. If the goal is to create a walled garden, people may simply not show up and go elsewhere because they like their porn, among other things.