I know it's not so hip here but the answer is money. You go to work for money. It's not to socialize, not for personal growth, and not for charity. If I want those things I have hobbies (including hobby programming.)
Most people would say no if they were offered a full time salary to spy on their friends, steal their data and act in a overtly unethical way every day. But these companies give them an abstraction layer.
There are plenty of things you can do for money that are not (or are significantly less) unethical.
