Also it doesn't really matter to the person being discriminated against whether it's a question of individual will or implicit bias, and we are still responsible for both. I will even argue that there's a high probability most white people have a lot of explicit bias as well, the reason I didn't mention that is because you can't test it empirically in the same way as implicit bias.
It's because most people by default adhere to a toxic combination of virtue ethics and retributive justice. Under that system, if you do bad things, the obligation isn't on you to improve yourself and your actions, but on others to make you suffer because you are a "bad person". People don't want to suffer, so they reject the initial premise.
Virtue ethics has its positives, but retributive justice needs to die in a fire.
You can see this in action above where jolux starts out using the first definition ("there is a high probability you have at the very least some implicit bias against non-white people") then switches back and forth.