Google is the only reason the Internet can be as big and fast as it is and still useable. You rely on Google to find the typo-ridden pages that you were looking for when you entered your typo-ridden search term. They're also trusted to avoid pages that will melt your hard drive to your motherboard with viruses. Being the bouncer at the door of the Internet requires Google to update their list of potentially malicious sites constantly and in real time. Getting added to that list is the closest the Internet has to a death sentence. Flagged sites either won't appear in search results or will appear with a warning message. Even if you ignore that message, you will be taken to a page that tells you to go back to from whence you came.
"My God, the dicks must have reached critical mass!"
Of course keeping up with the reams and reams of content pouring online at any given moment is no small order. Certain parts of Google's company can be automated, but there's always going to be some hacker trying to get malware online without Google noticing. And noticing requires humans, and humans make typos. That's how a misplaced backslash made the world wobble on its axis one Saturday morning back in 2009.