To me it seems that people don't quite understand the whole "holistic approach to admissions" that USAFA and the other SAs have. Yes, it does mean they look at academics, athletics and leadership, but as far as I know, USAFA Admissions actually does go for the "whole person." This is primarily evident in their request for a school profile from the counselor. If the board only cared about making money off of sorry kids who don't know any better, then they probably wouldn't have offered an appointment to someone with a 20 ACT score. But, because they want to know what exactly kind of school you're from, they absolutely want to know everything about you. Most colleges don't even care about what high school you're from for admissions. Even Ivies don't check that as far as I know.
Perhaps that person had 4.0 with all college courses for two years, maxed the CFA, was president and team captain of 7 different things and simultaneously worked a part time job to support his siblings, or to pay for a relative's cancer treatment, while still taking first at State sports and academic competitions. But he was just a bad test taker, or could only afford to take a single ACT and bombed it because it was the first standardized test he took in his life. And even so, a 20 on the ACT is only at the 51st percentile, so it's not as if a flunkie made it in.
Regardless, the "whole person" approach to admissions is really just that. There's a reason they go through so many difficult steps for admission including the nomimations process; they want to separate the wheat from the chaff. And even so, if you're fully qualified, you have a little under a 55% chance at getting an appointment, based on past years.
So really, just be the best person you can possibly be. If anything, seeing someone with a 20 ACT score should be emboldening, since that tells you that they care about you as a person, and not just as a number. They have to care, since you're worth over $400,000 to them.
Also, don't take this as a point that you can slack off in the ACT. This guy is absolutely an outlier, but likely an outlier in positive ways as well.