You set up your standard, and stick to it whomever comes.
1. A small company which is barely profitable but is building something which aligns with your values and you see as a positive to the world.
2. A massive mega corporation whose only purpose is profit, mistreats employees, and you view as highly unethical.
You shouldn’t treat those the same way. It’s perfectly ethical to offer your work for free to the first one (helping them succeed in creating a better world) and charging up the wazoo (or better yet, refusing to engage in any way with) the second one.
Interesting moral proposition, I doubt you'd get many followers. I think it's perfectly reasonable to treat people differently from corporations, and random small and medium corporations differently than huge megacorps without losing any sleep.
Specially in business, charging more to those that can pay more is a very common approach.
Well, the standard for software licensing is to sell cheaper licenses to smaller businesses and more expensive licenses to larger businesses.
Why? Most businesses don't entertain standard rates, either. It's case-by-case negotiations ("call us", "request quote"). Why should I, as a private person putting stuff out there for free, set up "my standard" and stick to it?
Tho pricing tailored to customers works, as long as it's efficient and non-zero.
