It sounds like you’re talking about ads on search results? I work on display ads and don’t know very much about the search side of things.
I don’t have any internal information, but some thoughts on the examples you’re listing:
Scammers placing ads is harmful, though not unique to advertising. The article you link describes a similar issue happening in the phonebook era. It’s very hard to tell from this sort of investigation how well a service is doing at avoiding abuse.
“Google Ads are regularly hijacked, such that they present https://youtube.com or https://bestbuy.com as the destination, but lead to a fraudulent website” Is this actually common? Looking at your link, it’s hard to tell what happened in that case but I think it was probably an open redirect on amazon.com?
I’m not able to find any examples of ads against “MapQuest” searching on my laptop or phone in a couple different browsers; you don’t happen to have screenshots?
“It’s in the best interests of Google for the consumer to click on an ad, not a search result. So even if Google has the best search result, it’s goal is to get the consumer to click on the ad.” This misses that there’s enormous value in giving users a good experience long-term, where they keep coming back.
But again, I know very little about this kind of advertising, since I work in a completely separate part of the industry.
Also an IT professional here. Google is among the less unsavory players in the ad space, but it’s a cesspool overall. Malicious ads seem to be one of the easiest ways to get that crap in front of a huge number of users. In practice I don’t see “reputable” providers directly serving malware: rather it’s generally a chain of redirects either implemented by the site they land on (that presumably behaves itself under indexing/due diligence), or by exploiting the ads on the landing site to cause a redirect. Ultimately lands either on an attacker-controlled site or just a site running an ad network that gives zero fucks or outright caters to cybercrime.
That said I made up my mind on this a while ago and I’ve been blocking substantially all ads and analytics for 5+ years. The game of cat and mouse may well have moved on.
I have definitely caught AdSense serving those super dishonest software download ads that pretend to be the download button on file sharing and software sites…
As far as you core concern, are you actually causing significant harm with your work, I really doubt it. Google has a decent incentive to crush bad actors lest govt. step in and kill their cash cow, and just getting the industry at large to match the mediocere level of ethical standads Google is upholding would still be a huge win. Ads suck as a solution and cause a fair amount of preventable harm, but harm reduction is a legitimate thing to work on. Bonus points when you can pressure competitors to shape up and not be too evil.