Harvard and the other Ivies don't want to keep out asian people. They want to keep out boring, myopic applicants who spend all day studying to achieve the grades and scores they have and show little sign of interest in contributing to the outside world beyond getting a well-paying job as a lawyer or doctor and raising a family comfortably.
The Ivies get thousands and thousands of applications like this: with incredible academic credentials but nothing else to recommend the applicant. They could fill their entire classes with just applicants like this. And this cohort of applicants just happens to be very very very asian.
In a way it's not dissimilar from how VCs want to invest in founders looking to go big. Founders working on lifestyle businesses are not worth their time. Ivies want to turn out a lot of professionals yes, but they also want to turn out artists, politicians, bankers, military officers and so forth.