If I need a job, if the money is right my ethics are negotiable.

This is the norm.

Sure; but then don't also try to justify the action by saying someone else would have done it in your place? "I need a job, even an unethical one, and refuse to feel bad about that" is a completely different argument than "I would have been replaced by someone who would have done the same, and so don't need to feel bad about it".

I think history has proven that there will always be someone willing to do what hundreds of millions of people wont

Certain bad things that people used to do don't happen anymore. This must mean that, in general, actions really do matter -- even if it is very hard to know ahead of time which ones will have a significant impact.