Taking 11 AP classes when all those APs impacts the grade (as they did here) is certainly going to be more detrimental than not being able to take one specific AP class.
One other thing that @Sally_Rubenstone did not mention: most high schools prioritize staffing to ensure that courses required for graduation are covered before assigning teachers to elective classes. So if an AP class is at capacity, it’s not likely that an additional section can be rolled out. So in that case, prioritization based on past grades (and class year) is fair and equitable.