Showing countless instances in where you non-racistly interacted with another race seems tedious, and it also technically doesn't prove you haven't been racist in other instances that you aren't mentioning. You can demonstrate that your social group is multiracial, even particularly so, but the public seems to quickly discredit that as a viable means of proof of a lack of racism. And a lack of racism isn't tangible. You can prove to someone that someone robbed a store. You can have the tape and show it to the judge, you can find the stolen product and present it to the court. There is real, tangible evidence of things that did occur. But how can you prove a lack of occurence? How exactly can you prove a lack of racism?