If you commit a crime because somebody else asked you to do it, does that mean you didn’t break the law?
If Facebook commits a crime because someone asked them to do it, does that mean they didn’t break the law?
How could the answers to those two questions be different?
As another example - should Facebook be legally responsible if I use their service to send death threats to someone? If not, why is that case different?
Government will have to step in.
"But having humans review ads doesn't scale!" says someone with a financial position in online advertising.
Meanwhile, the massive profits of the online advertising companies have forced them to 'pivot' into real estate holding companies, during a period of persistent underemployment and stagnant wage growth.
Yep. Nothing can be done. We have to wait for artificial intelligence to save the day. It would simply cut into profits too much to follow the law.
In many cases, the answer is no, you did not break the law.
The best example I have of this is DMCA, and copywrite law. It is perfectly legal for youtube to allow users to upload content that they don't have the rights to, as long as they follow the DMCA takedown process if requested.
Or to give another example, think about your phone lines. I am sure that many users engage in illegal behavior over the phone. But it is not the job of the phone company to listen in on your phone calls, to ensure that you are, I don't know, engaging in harassment or some other illegal phone activity.