Why aren't advertisers (Microsoft, Facebook, Google) held responsible for allowing scammy adverts?
I know they allow scam adverts because it's easy money, but why aren't they held responsible for facilitating obvious scams? You open Edge, there's 3 "Earn money quick" adverts. On Instagram, every 5 ads, one is a scam.
It is the law's job to prevent and stop scams not of the platform that provides the advertising
If I had a printing shop (not sure how is it called in English) should I be the one who checks that what is written on the handouts is legit? Heck no, I don't have the means for that.
It's not just that, there are laws preventing a lot of stuff (not that it's not commonly happening anyways). For instance a huge thing was never copying anything with Disney characters in it. It's not like Disney has a special rule only for them, it's just that Office Depot knows they're the ones to sue your ass into dust if you get caught. It's the same for any copyrighted material if it's going to be distributed, but OD ignores it for the minor stuff because it's low risk. We just need to laws to protect us from these malicious practices and then we need them to be enforced.
You can't print whole books if your costumer asks you to without having permission to do so, you would be a distributor. If you ask the question "if I do something illegal or harmful to someone, should I be taken responsibility?" you can get a better answer. You don't need a third party to take ethical decisions for you. That's the point of the thread, ad companies have knowledge about harmful ads and refuse to take them down.
Any service you offer professionally should absolutely be reviewed for legality. If you didn't have the means to comply with laws and regulations you shouldn't be in business.
And in the case of lots of these ads with malware, it would be like you printing poison ink on handouts, and saying you aren't to blame.