The perspective of what good and bad is, is very subjective.

Making weapons = bad

Making anthrax = bad

Making weapons which kill your enemy (aka the one trying to kill you), which are more effective, could actually = a less bad company. If you are a patriot, then working for a company like Lockheed Martin may be seen in your own eyes as good. Same with FB, it is connecting the world (Trademark Zuck).

Coal Power is bad, for the environment but it is good for society as we need electricity.

So there are two perspectives to this, how you judge yourself and how others judge you. The internal is based on your own views, and the external is based on 7+ billion views and there will always be conflict in both.

So to answer your question

> Who decides what 'bad' is?

Everyone and no one. It is a paradox, and the original `No` answer to this question would be simplistic and out of touch with reality. The better question is, if I know the company I am working for is against my moral, ethics then does that make me bad?

the person that is working at company X, decides for himself if X is bad. If this person believes that X is bad, he should IMO resign to stay healthy.

Even when I worked for a large defense company which built systems to kill people at war, there were good aspects of it. There was one group that was building systems to monitor the rainforest. Another group was supporting the antarctic scientific missions.

There are also people that work to change the organization from the inside out. To be honest, if you want to change corporate culture, that's how it has to be done.

Yes to all 3 questions.