This is because, as a developer, you're a user who understands and knows what you want. Microsoft is writing software for the kind of people who'd type google into the google search bar to get to google.
I've done that, intentionally. Do you know why? Because between Microsoft deciding that anything that isn't at least a second level domain is a search request intended for bing and Time Warner deciding that anything that isn't immediately properly resolveable should be DNS redirected to their own god-awful search-like landing page, that can be the most reliable way to get to where I actually want to go.
I usually have set my DNS to OpenDNS, but if I've rebuilt the machine or traveled and stayed somewhere that mysteriously breaks my manually-specified DNS server, I may have reverted the notebook to use whatever is automatically set by DHCP.
I usually uncheck software's constant attempts to make [insert name here] my new default search agent, or to activate some added search suggestion do-hickey, but I'm not perfectly vigilant.
Nevermind that this browser will automatically assume "www." and that browser will automatically assume ".com" and maybe, but not consisntently, if you type "google" you'll actually get to the Google front page.
The kind of people who type google into the google search bar to get google are the kind of people who are not so technologically savvy that they can consistently prevent the ever-loving war to redirect any user typing something into what should be a URL entry field to some random "search engine" because user traffic = middleman $$$.
THE UNIFIED SEARCH AND ADDRESS BAR IS TEH DEVIL.
The Bing toolbar, Google toolbar, or what have you can be ugly clutter, but it can't be subtly screwed with by the other devils.
And that is why you get people typing google into the google search bar to get to google.