You're comparing a known with an unknown. We can judge that the known is unethical. We cannot judge either way on the unknown. It follows that the only possibly

You're comparing a known with an unknown. We can judge that the known is unethical. We cannot judge either way on the unknown. It follows that the only possibly ethical choice is at Smallcorp. And I'm sure we could make a much better argument for it if we substituted Bigcorp and Smallcorp with actual options you were deciding between as a prospective employer.