So what does Apple CEO Steve Jobs have to say about the furor? In typically terse e-mail replies to Apple developer Greg Slepak—who told Jobs “I love your product, but your SDK TOS are growing on it like an invisible cancer”—Jobs gave the nod to an explanation by Daring Fireball’s Jon Gruber about Apple’s reasoning and said letting others in the middle leads to sub-standard work. Apple doesn’t want apps to work the same across devices; it wants iPhone/iPad apps to be singular and best used on its own devices.

The e-mail exchange is posted here. Gruber, who who first noticed the change, followed his original post by explaining why the lockout makes sense for Apple. Jobs calls that post, which concludes that Apple is doing the right thing for the company and its users, “very insightful.” Gruber offers the difference between the native Kindle app for iPhone and the not-native (and not as good, he says) Mac version as an example. Jobs’ reasoning: “We’ve been there before, and intermediate layers between the platform and the developer ultimately produces sub-standard apps and hinders the progress of the platform.”

Here’s a bit from the Gruber post that Jobs seems to endorse: “From Apple’s perspective, changing the iPhone Developer Program License Agreement to prohibit the use of things like Flash CS5 and MonoTouch to create iPhone apps makes complete sense. I’m not saying you have to like this. I’m not arguing that it’s anything other than ruthless competitiveness. I’m not arguing (up to this point) that it benefits anyone other than Apple itself. I’m just arguing that it makes sense from Apple’s perspective — and it was Apple’s decision to make.”