You cannot resolve prior inequities by forcing students into college- they drop out at higher rates, with higher (unforgivable!) debts, and word of mouth of their experiences will continue to deter others from trying.
I personally witnessed this happen to friends I had made my freshman year at school.
The ACT in particular has a really low bar for anyone who does reasonably well in school- most state schools around here had a minimum score that certainly required no preparation to achieve.
Alas, my alma mater did not, and it was pretty obvious to everyone that they were athletes first, and kept up appearances about schooling. I am reasonably confident that several degree programs that the school offered would not have existed if the football and basketball programs didn't exist.
Would they have been able to let in more students who would have bean more focused on schooling? Honestly, I don't know, but I strongly suspect there are lower hanging fruit to pick first.
Second, you are not offering an alternative solution that would be preferable.
Also, you are not recognizing that fixing in the top 6% is not a requirement for admission so it is possible for the situations you list to be addressed.
Finally you end with an argument against standardized testing which has nothing to do with the comment you are replying to. In fact the 6% policy allows a student to get into the university without ever taking a standardized test.
> Or consider being a minority in a very white district that isn't fond of minorities
For example these people by your own definition will be rare. They might also be disadvantaged in other ways should they live elsewhere, which means that that the same person in two different places would simply face a different set of disadvantages which might even themselves out. Likewise "a district that skews wealthier" should naturally have fewer "have-nots" than other districts so "have-nots" themselves would not be disadvantaged on average.
* Consider a family where the highschool student has to work to help out with rent and food bills, so they miss school or don't have time to work on assignments. Compare this to a wealthier family where the student has all the free time in the world.
* Or consider a district that skews wealthier and tutors push the haves up into the 10%, and push the have nots below. Plenty of the have nots would have hit the 10% threshold if only they had money.
* Or consider being a minority in a very white district that isn't fond of minorities.
These are just a few I've read about off the top of my head. The idea of standardized testing is fair, but only if it is aware of inequities in the system. This has been a debate since the 70's. In fact, the popular TV show "Diff'rent Strokes" did an episode about systemic racism in standardized testing the early 1980's.
I'm not arguing if Cali has it right or wrong, but there are problems with using just testing.