It's a totally unfounded assumption. In lieu of evidence is a claim based on a single teardown by somebody who assumes it's an auth chip purely because he didn't recognize it.
The Thunderbolt connector is also chipped, but it's a multiplexer. After all, with nine pins at the Lightning end and four pins + shield at the USB end, it would make sense to put some logic in the connector, too. You can't simply run a wire from one pin to a totally different pin and expect things to work, the way you can with most analog and some simple digital connectors.
I trust AppleInsider only less than I trust Weekly World News. Unlike the WWN, AppleInsider will print anything.
Setting aside whether or not there's a chip, the main challenge at the moment is finding a way to connect the USB-A-male end of the Lightning connector to the USB-B-female end your DAC-of-choice. I've got a few different DACs available to me, but they're all either full-size USB-B or micro-USB. Hypothetically there are adapters available, but I haven't see one. And an adapter might not be adequate -- if Apple's standard Lightning connector is just USB data and power, you might need a different connector to access the dedicated digital signal out.
I'm guessing we'll have an answer from somebody by the end of today or tomorrow. Team Diary's not the only bunch of people interested in this question.