Its better to blame the management and higher ups or zuck himself directly. Blame the people who finance it and profit from it, not the people who coded it. Follow the money
I remember finding this out as a very junior engineer straight out of university. I was once asked to write code to cheat at a benchmark to make my company's product look better than it actually was. I had deep misgivings about this, but as a brand new junior developer, I was very hesitant to speak up. Eventually I told my manager I didn't feel comfortable with the ethics of working on that project, and he was totally cool with it! He said "No problem, we'll take that task out of your queue and give it to "Jim", he'll do it instead." Jim was thrilled and wrote the benchmarking cheating code himself.
There's always someone willing to do it.
(also, is it an exciting technical challenge? It’s a POST request to localhost!)