Service academy recruiting is a different animal in a number of ways.
First, service academies are not limited by the number of participants and scholarships like other schools. There is a specific clause in the NCAA Manual that states:
17.9.2.1.2.3 Exception—National Service Academies. [FBS] There is no limit on the number of student-athletes who will be attending a national service academy and who may engage in practice activities prior to the institution’s first day of classes or the institution’s first contest, whichever occurs earlier.
As everyone is essentially on scholarship and the 105 participant rule noted above is waived, this means that they can bring in large recruiting classes each year.