It begs the question seeing as they've written a bot to determine what's offensive why don't they hook it directly to the ad servers and auto disable ads on the offending pages only?
I detest Google, so I absolutely have to say this is an absurd way to look at the world. Google doesn't care if it's actions are pro or anti consumer, they care about money and power and go about pursuing it in a way that tends to be anti-consumer.
Neither are the ads they serve; furthermore the amount of profanity detection required scales linearly with the number of pages on which ads are served, so this really shouldn't be a barrier.