Of course you are free to boycott them if you so wish, but boy do you need to boycott a lot of people if you apply this strictly. There are other systems in place to take care of this, which may or may not require additional work (such as justice system not being as strict with rich people), but that's a separate question.
No, I can't save the world on my own, and nor can anyone. I've done a good many things which have directly and indirectly resulted in harm towards others, because I need to in order to survive in today's society. But that's not the point - the point is to build an ethical framework in which we can aim towards intentionally enabling less harm, even if we can't ensure no harm.
In more realistic examples than the one outlined I believe it's almost always the case that:
(a) people are doing a bad job qua something, such as journalists not having journalistic standards, etc, or
(b) people judging someone outside of their "known" domain almost always over-react and misunderstand (see witch hunts for people that should be dealt properly by, say, the justice system). I.e. the side effects are generally more harmful, at least if you impose it on others.
(I should follow my own rule of never replying to my own thread outside of simple questions. It always bites me. Especially ironic how all the points in OP and my original comment applies to this thread.)
Sounds like the value proposition of white power music, or some rap.