Imagine that you’re standing on a train and have a baseball. If you throw the ball off the train, the ball will still have momentum in the direction of the train’s movement.
If you want to throw the ball to a friend the train just passed, you have to be able to throw the ball faster than the train is moving or it will never reach them.
If Google takes money to host an ad that’s malware, they should be able to be prosecuted for it.
This is different than simply hosting community content that they can’t reasonably moderate. They’re being given money to distribute these ads, so they can afford to moderate them.
Which should be easy anyway. Ads shouldn’t be able to install third-party shit from the advertisers on user computers. Google can easily restrict what can be included on an ad package.