Absence of evidence is not evidence of absence. Often, it just means that we haven’t figured out how to identify it yet…especially when it comes to something as confoundingly complex as human psychology. Thirty years ago, was the public really aware of, say, ADHD or autism? How much of the general population still thinks that sexual preference is a choice?
Am I going to prove to you that implicit bias exists? Of course not, for in my experience, one doesn’t learn through argument nearly as much as through experience.
There was one other commenter who said much the same as you, and here is my reply to him (to save me from typing that long reply all over again).