HN isn't just about software/engineering, it's also about entrepreneurship.

Tesla is a startup with cool technology. They're taking on a market where startups never succeed and are navigating significant challenges regarding new technology, consumer bias, competitors, regulatory issues, business model, press relations, and more. Some of us find it fascinating and enlightening to watch them take this journey.

Edit: Reworded.

The Tesla Motors post that heralded this news (https://news.ycombinator.com/item?id=6240862) was on the front page for nearly a full day and garned 794 upvotes. HN readers are clearly intrigued by TM

Because it's getting upvotes, mostly.

Because Elon Musk is god here and worshipped.