The front page is not generated dynamically, to cut down on bandwidth use. Every 5 minutes or so, the server regenerates the front page, and that's when the vote counts will get updated.
As far as I'm concerned, it's a topic of conversation, nothing more. Passersby with no interest in the story whatsoever can vote in order to, ummm, have something to do, such as upset the Mac fanatics.
Back before the iPhone was released and we posted a story about iPhones browsing MacRumors from an Apple IP address. That iPhone user rated the story positive.