If they did it on merit and pure numbers, 50% of the class would be Chinese. No one is ready and wanting that.
Not sure whether “pure numbers” serve as the best measure of “merit.”
You would have to factor in more subjective considerations such as strength of curriculum, strength of school, etc. to put the numbers in context. Also, top-notch SAT scores are somewhat meaningless because far more people attain near-perfect scores (around 1500+, out of 1600) than there are places available.
Extracurricular achievements are important because they tend to distinguish students who are able to do well academically while balancing other commitments (as well as more well-rounded individuals generally) than those who merely study to get good grades and test scores. Essays and recommendations are used to assess an applicant’s writing abilities, work habits, and intellectual curiosity. Pure numbers do not necessarily or accurately reflect these attributes.
For the most part, the students at Yale (and at Harvard, Princeton, etc.) have the “merits” to be there. Whether they take advantage of the enormous opportunities there or end up with common sense views on politics, economics, etc. is ultimately up to them. Many students tend to be liberal, but they are not the “social justice warrior” types who seem to grab all the headlines.