I know what you are saying, but actually this service is free. Blocking bots effectively is in both the website owner and Google's interests, because bots disrupt the value propositions of both. And you could argue that it is in the website reader's interests too, by extension.
Given their scale and resources, Google are able to provide a far more effective bot detector than any of us could do on our own. I for one am delighted they are providing this very valuable service.
Not sure what blocking bots have to do with the freeness of the service. Perhaps you'd like to reply on one of the comments further down to get into why you believe the service is free?
You may argue that the trade is in the website reader's best interest. This is a different argument than whether it is free.
Given their scale and resources, Google are able to provide a far more effective bot detector than any of us could do on our own. I for one am delighted they are providing this very valuable service.