I understand why Valve lost, though I didn't agree with it. I don't want Minecraft to win, but there isn't anything that has stopped it so far... that depresses me a little bit.
What people are saying is that this one creativity toy is better than any of the series that people re-make in it. Just think about the number of Mario levels, old school sprite graphics, game remakes and other homages that make up Minecraft. Now consider that were you to vote Mojang, you'd be saying that you choose a sandbox over the entirety of your lives as gamers. More than Mario, Sonic, Link, Kirby, Marcus Fenix, Solid Snake, Alucard, Pac-man, Kratos, Hawke, Bayonetta or any other character from any game series you can name.... combined!
It came out in 2009, and it has already received plenty of more appropriate awards and accolades. Give this one to Bioware. They've deserved to win and only gotten to second place... what, 3 years in a row?