My guess is that there is no set standard in law. When you deny someone else “equal opportunity “ they can challenge the denial to the FCC and in court. Whoever loses the FCC appeal files a federal lawsuit. Then it would be based on case law for the definition of bona fide in similar cases and, barring that, similar usage of the term. You duke it out with $1000/hr lawyers in federal court for 2-3 rounds until the most recent loser appeals to the Supreme Court where they turn youdown or you argue if the FCC even has the power to compel such an “equal opportunity “ based on the law which allows the rule to be written.

At least that’s my layman’s understanding of the process.