Why is Google profiting from Spyware/Adware?

After trying to help a friend clean off their computer, I realized what the main reason why so many people's computers are infected with this junk: Google and Money. I believe that google is the #1 linker to spyware. Search google for words like "smiles" and you'll find loads of software links on the right, on the paid listing side. Things like "hotbar" and "smiliecentral", which have been deemed adware by some. Once you get these installed, you try to search for "ms antispyware" and find a sponsorlink for "ms spyware" and find a link to "Microsoft antispyware" from spywarecleaner.com... which is probably some pretty serious spyware as well. So, why doesn't Google just ban adware and spyware in their listings and ads? Money I guess. I think we need a real movement to force Google to modify their policy. "Do No Evil"(tm) they say. I call their current policy evil, and I think they should change.