"You pick an issue, with 10 imperfect solutions over 50 years"

Are you suggesting that disparate impact is part of a delicate system that reduces or eliminates unfair discrimination? And that its elimination would make the situation worse than it is today?

If so, why?

I've given you many reasons why disparate impact is bad and has bad effects. You have given no reasons why, with the state of the country as it is today, it is helpful. Your argument seems to boil down to (i) well, there must have been some reason for its introduction, and (ii) status quo is a fragile system that must be changed all at once and not piecemeal.