> big oil? Their products kill people literally every day.

Does oil kill more people than lack of oil though? How many people would starve without synthetic fertilizers (made from oil) and without oil-powered farming equipment?

Yes, I personally think so. It's a difficult comparison because the effects of Facebook are not obvious physically, like e.g. tobacco is. That makes it even more dangerous because it seems safe. But the negative effects of mental health and misinformation (politics, health, etc) also indirectly kill people or make them miserable, it's just not a direct association that's easy to measure. These effects probably have a larger negative impact on the world overall than something simple with obvious effects like tobacco.

Its not about more/less evil and ranking, its a simple question of would you refuse to work for X.

I've been approached by FB recruiters, or their bots probably, and simply ignore them. The way I determine a gut reaction answer to "would you work for X?" is how you would feel answering when someone asks what you do for a living. I'd feel queasy saying I worked for FB because I feel that they indirectly cause massive harm to society for profits.