What does it take to advertise on Facebook to people who openly call themselves “Jew haters” and want to know “how to burn Jews”? About $10 and 15 minutes, according to what the investigative nonprofit ProPublica recently uncovered.

After much outcry over this revelation, Facebook’s chief operating officer, Sheryl Sandberg, called the anti-Semitic ad targeting “a fail on our part,” promised to put more human reviewers in place, and said the company “never intended or anticipated this functionality being used this way — and that is on us.”

Some of Facebook’s users may find it even harder to accept what happened. How could the site that we use to keep in touch with friends and family, share baby pictures, and keep up with politics and volunteer work be made so easily to cater to the interests of Nazis?

But anyone who understands how Facebook works shouldn’t have been surprised. That’s because the same digital platform that offers us social interaction, news, entertainment and shopping all in one place makes its money by making it cheap and easy to send us commercial or political messages, often guided by algorithms. The recent scandal is just a reminder.