So once we get past the academic-merit-alone standard the field widens. Individual Universities can craft a class that matches the culture, history, and traditions of a school. Some may say these things don’t matter. I disagree. For universities with strong history of athletic programs, it makes sense that they provide some preference to athletes, some with academics that don’t mach some students who are not admitted. These athletic programs also deliver marketing “goodness” to universities and build thriving alumni groups. For other universities that don’t have athletic programs I’m not sure that any athletic preferences are given at all.
What other preferences a university uses to craft their student body is up to them and is an inherent part of how they build their mojo. Some say that students with celebrity parents or parents from big businesses should not be given preferences and the same for legacies, but from an admissions pov it makes perfect sense. They too help build their community and cachet.