This whole debacle is sort of humorous. I fully support the rights of workers to unionize. The problem is in "Non Right to Work States" the unionized can clobber people that choose not to unionize and coerce them into participation. This is incredibly unethical, immoral, and unconstitutional and violates a person's right to self-determination and other human rights.
So the thing which is "unethical, immoral, and unconstitutional and violates a person's right to self-determination and other human rights" is not what the heirs did, but what the workers doing all the work and creating all the wealth did. No questions about the province of the heirs. You're dealing with both these groups but questioning the paternity of only one of them, the ones actually doing all the work and creating all the wealth.