I must be misunderstanding this because the way I read it it invalidates itself. If we suppose that we cannot solve the problem with individual ethical choices

I must be misunderstanding this because the way I read it it invalidates itself. If we suppose that we cannot solve the problem with individual ethical choices, and taking part in political action is indeed an individual choice (let's assume ethical), then organized political action as an aggregate of individual ethical choices cannot solve the problem. Separately from that, I'm skeptical that a majority-ruled political system that largely runs on "donations" from unethical companies will be moved by an ethical minority.