There is a fundamental difference when you're talking about a stock-owning, educated, in-demand software engineer, even if they are "just" working on scaling Facebook's image service. They have the institutional power at the company that they could leverage to change the product's outcomes, if they so desired.
Institutional power doesn't have to be leveraged towards political ends, but if you profit directly from an institution choosing unethical behavior in pursuit of profits then you are also behaving unethically. It's completely reasonable to apply that standard to the best-paid of Facebook's employees, just as it is completely reasonable for those employees to petition against committing more unethical behavior.
Facebook themselves already admitted that they were used to further a genocide, so your dismissal is somewhat beside the point.
https://www.nytimes.com/2018/11/06/technology/myanmar-facebo...