Without looking to far into it, the comments section seems pretty diverse and rife with various posters. How is he spamming his own comments?
Based on an article I read about it, he was posting answers to some backers questions - but doing so several times in a row, which had the effect of pushing negative comments far enough down the comment list as to no longer be visible without digging for them. When his backers cried foul, he claimed his computer or account was hacked - which no one believed.
This isn't the first time I've heard of something like this. While Kickstarter never comes outright and says it, they're a de facto marketplace. But the one thing they do actually prohibit is creating a project for the "creation" of a product that already exists, which most people now believe was the case. In this case, it looks like he took the S3 smartwatch and simply altered the branding.