AdBlocking is 100% OK, that part is correct for sure. Ad networks (including Google's) routinely serve up scams and malware: It is foolish not to use a browser with a fully functional ad blocker at this point (i.e. avoid Chrome, use Firefox with uBlock origin).
As for whether Google approves: Fuck Google! They have been serving up malware and scams in their ads. Their opinion should be irrelevant if you have any interest in protecting yourself, they have repeatedly proven they cannot and should not be trusted.
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.