> So should we implement systems that target suspects based on the color of their skin? Obviously not.
Why not? Why is that obvious?
Utility: if the system isn't effective, there will be additional crime and additional victims of crime ('''bias''' against those victims)
Group fairness: the system should target the population in a uniform manner across all skin colours (actual statistical bias to favour skin colours over-represented in crime)
Procedural fairness: the system should follow the same process for all skin colours ('''bias''' against skin colours over-represented in crime)
In a world where skin colour isn't uniformly distributed across crime rates, you can't have all of those. You must explicitly sacrifice one of those factors to have a chance of satisfying the other two. Ignoring this trilemma doesn't make it go away. No matter what you choose, including inaction, there will be a harmed party.
This was an actual scenario faced by the COMPAS parole sentencing system. There are no easy answers.
P.S.
You are surrounded by systems that target you based on the colour of your skin every day, and the designers of most of them aren't even aware of it. Scandals like 'Woman slams ‘racist’ Boots for putting security tags on hair products for black customers but not those aimed at white people'[1] are driven by very simple models and very limited data like [sku, shrinkage rate] that you would think can't possibly give away skin colour. And yet they do. And if you want to make those models 'not racist' then you do actually have to statistically bias them on skin colour. Again, no easy answers.
[1] https://www.thesun.co.uk/news/9941383/boots-racism-security-...