Dumping toxic waste in the town square is illegal. If what Facebook is doing is so bad, why can't you assemble a political constituency to make it illegal?
Is it possible that this "every FB engineer is a moral criminal" stance is actually a fringe view espoused by a radical minority and not a principle we should consider seriously? I think so. I reject the OP's claim to moral authority.
A thing isn't bad just because some random commentator on HN says it's bad. The law is how we encode legitimate and society-wide consensus on what's bad. I am under an obligation to follow the law. I am under no obligation to behave according to what some random HN commentator wants to ban this week.