It's not hindsight though. The problems with the ad economy were always known. Page and Brin pointed it out in the pagerank paper. Altman said ads would have to be a last resort (so he knows it's wrong), and then they did it. The employees there are in high demand. They didn't have to help build it, but they did. People who build TVs that spy on their owners know what they're doing is wrong; it's literally famous dystopian sci-fi. It's not that they didn't prevent something: they built it with eyes wide open.
Or like the gambling thing: it was already illegal. All they had to do was not make the world worse. The saga that led to its legalization started with a voter referendum. Then other states jumped on the idea and took it further. No one needs hindsight to realize universities pushing their students to gamble on sports is evil. There's no "that's how it's always been" to excuse themselves; they thought of a new way to exploit young people and did it.
In any case, even if you grant them being merely indifferent instead of malicious, that still earns them indifference toward whatever troubles fixing the damage they're still right now bringing might cause them.