True, nothing on the LSAT prepares someone for legal practice. But it provides a back-of-the-envelope measure of aptitude in law-adjacent skills—primarily logical reasoning and reading comprehension. And studies have consistently shown that LSAT performance is the single strongest predictor of academic success in law school.
So why oppose it?
Criticisms of the LSAT largely echo criticisms of standardized tests more generally.
Essentially, they boil down to the claim that the LSAT does not objectively measure ability because children from wealthy backgrounds can more easily afford elite prep courses and personalized tutoring.
It certainly seems unfair that such a significant portion of the admissions criteria favors the wealthy. But even critics of the LSAT concede that the same is true of nearly every other component of the admissions process. The wealthy can hire tutors to improve their GPA and snag better recommenders. And they can pack in more extracurriculars because they are less distracted by resource requirements.