I think that it is unethical to use an absolute cut-off filter without informing applicants. Students pay not only ERAS fees but may also pay application fees to the interested program.
If the program spends time to look at the application and makes a reasoned choice to select a candidate with better board scores, then that's fine. A program could also use a rank formula whereby it ranks candidates based on class standing and board scores. The most promising get interviews. At least with the rank formula, the program made an effort to compare the candidates. A student without the criteria for Harvard who applys anyway deserves to lose his money.
But to have an administrator filter the applications by just a numerical cut-off while collecting fees preys unnecessarily on the aspirations of vulnerable future members of the profession. If a program decides to collect fees, then it should spend some effort to earn those fees.
In litigation, a program can prove its sincerity if it has a history of choosing candidates with lower board scores than the statistical cut-off.
There are a lot of unethical things done in this profession. Those things will continue until programs get sued, win or lose, to make such practices no longer viable.