> They are as clean as they can be

Indeed, which is to say not clean at all.

"Only slightly dirty" and "much dirtier than mine" are fine judgements to console yourself of your involvement, but if you intend to indict a man, you'll need much stricter standards than this.

To be completely clear: I agree with your moral assessment. I too would not work for Facebook due to my moral qualms with the company. However, it is a terribly dangerous game to begin judging a man's choices when you know nothing about him.

Before long you'll convince yourself that you're the only decent man around and the rest are less-than-human.