Don't ask me. Ask Justice Thomas. Continue to believe what you will. It is highly offensive to make the assumption he only is where he is due to AA. You have no idea what his LSAT score is, and it is the biggest factor at every IVY league school. A high LSAT can overcome less than stellar grades, but the inverse is not true. Your comments are the living definition of bias, and you don't even see it. AA is a program that creates a bias as currently implemented. The difference between the average admission scores at Baylor vs the average for blacks is a lot more than four points. And four points on the LSAT is huge. That could be the difference of Yale instead of University of Utah. Huge. U of Texas allowed a student in with a LSAT of 128. You get 120 just for writing your name.
Racism will always exist, it doesn't mean it is OK to have programs that exacerbate it. Additionally, most law students are upper middle class regardless of race. The fix is not at the admissions level, it should be before, and it all goes to the disadvantaged poor, again, regardless of race.
And in regards to what is allowed under the constitution, there is no protection against class. Race, gender, and now sexual orientation are all protected, and to be defeated a program must pass strict or intermediate scrutiny, which are nearly impossible to overcome. For discrimination against class (or anything else that is not a protected class), you simply have to pass a rational basis review, which is easy to do.