It is easy to rail against employers for showing the complained about bias against minorities and women. And doing so is clearly against the law. However playing Devil's advocate it is justifiable by the fact that hiring decisions are naturally risk adverse. The difference between a perfect hire and a merely good one is typically not that big. The difference between a hire that works out and one that does not is huge…
According to you a couple black people got farther than they should have because of affirmative action and because of that you wouldn't blame an employer for considering all black people "risky" hires. Doesn't that sound a bit ridiculous? Put another way, has anyone ever said "a couple white people screwed over the team a few years back so we think twice nowadays before hiring white people". Or "we found that guys seem to slack more during work hours and now we shy away from hiring men". Of course not, because white and male are normal when it comes to jobs in tech and so they enjoy the privilege of being treated as individuals. To drive the point home your bias is obvious in your comment - "you're going to naturally think 2 and 3 times before making a similar hire" - "similar" applies to black or female because it's understandable to aggregate those individuals, their actions easy fit into a narrative that already exists in your mind. Pick two white men at your work who consistently perform poorly and I don't think you would be as comfortable attributing their behavior to their race or gender.