That's false. The one area where I'm sure google doesn't mess around is with their ads division. They spend a proportionately large amount of money combating fraud to prevent erosion of confidence and most importantly accuracy in their main money maker.
If you've ever taken a look at the number of conversions fb ads provides vs google ads, you'd know this.
Agreed, especially where most of these clicks can be carefully audited and reconciled by the advertiser, it would make no sense for Google to threaten its reputation and primary money maker.
Edit: that being said, this does not seem to hold for Facebook, and I don't have a good reason why.
Google's advertising business is built on trust. The moment there are a few scandals involving fake/robot ad clicks, big advertisers will remove their ad campaigns.
Google is the only organization with the data to show this happening at scale and they don’t have incentive to connect all the one-off anecdotes.
So while it is risky, not sure how they could be caught. I don’t think they are running click fraud bots, but it’s hard to quantify how hard they work to stop them.
A friend of mine estimated that 1/3 of ad spend is click fraud but it’s just in the wash because it’s hard to stop.
Google has a strong incentive to let them.