MemeberLG makes a very good point.
The academic standards for admission are high, not because West Point is trying to be elitist, but because West Point is tough academically.
You don't have a lot of non-class time to yourself. You have duties, athletics, drill, formation, required meetings, mandatory meals, etc. You have study time x hours/day. You have more than you can do in 24 hours. Priorities have to be made. Decisions on what can slide for today and what can't.
Every cadet graduates with a BS. So no matter what your major is - you will still have 2 semesters of Calculus, Chemistry, Physics, History, English and Foreign language each. You will take about 18 hours or more a semester. A heavier load than most of your civilian college friends. Did I mention that West Point is academically tough?
This is not meant to scare anyone. If you are offered an appointment, West Point is saying that based on your application, you can handle the academic rigors. The way you prove that to them is through your test scores, GPA and class rank.