They should not admit students who have little chance of success
Sure, but these students are likely two groups; those who are never going to be good at math, and those who were never really taught math.
The latter may need an opportunity to succeed.
It's difficult to assess which students have a chance of success without standardized testing.
"In 2024, over 25% of the students in Math 2 had a math grade average of 4.0".
Math 2 is the remedial elementary and middle school math course at UC SD. Lack of standardized testing plus grade inflation contributes to this outcome.