Pages with tag Google Adsense

Google Adsense shows ad leading to site Google knows is bad/dangerous - WTF? I just clicked on a Google Adsense ad - the ad text made me curious - and immediately shown a WARNING screen of a "Deceptive Site Ahead" that might install malware etc. It is nice that Chrome is there ready to shout "Warning! Warning! Danger Bill Robinson!" But -- I got to that screen by clicking an ad hosted by Google Adsense. Doesn't one hand of Google know that the other hand of Google has said that site is dangerous? Why doesn't Google block advertising that leads to dangerous sites?