Or the third source of bad traffic: Third parties you have no control over heating clicks because of free registration spam, comment spam, generating "legitimat

Or the third source of bad traffic: Third parties you have no control over heating clicks because of free registration spam, comment spam, generating "legitimate looking" accounts for later credit card fraud, or plain ddos reasons. And there's no human being to discuss this with, or even get details from. Note that this blog itself has dozens of suspicious or obvious bot spam comments. If Google can't filter this out, how am I supposed to?