jayawayjayyay

Doing QA at large tech companies is never that simple. You have lots of teams that share code. Imagine a scenario where Team A uses code written by Team B which uses code written by Team C. Team C makes a change to their code that breaks Team B's code but only for the way Team A uses it.

From the article it sounds like there was a prompt for permission that got removed:

> Facebook told Gizmodo via email that in May 2016 it made a revision to the registration process, which originally asked the affected users for permission to upload contact lists. That change removed the opt-in prompt, though the company did not realize the underlying functionality was still operating in some cases.

It doesn't take a conspiracy to understand how a bug like that could happen.