“Why shouldn’t we always conclude that if a white policeman kills a black suspect then he surely had a good reason to do so without bothering with the facts and evidence?”
But this is what always happens in America. Time and time again you can take a random sampling of white Americans, put them on a jury, and inevitably they will justify a police officer (of any race) killing an unarmed Black man. This happens regularly and rarely with exception. Black people are consistently seen as guilty and responsible for their own deaths at the hands of police officers.
And let’s be honest here — if there is a racial difference between a shooter and the victim, race always comes into play because that is how this society was established and it is the dominant mode of thinking in this country. Black people didn’t arrange things in this fashion, the descendants of Europeans did. Skin color matters ALL the time.
If there was an epidemic of police officers of colors wantonly shooting and killing white mean and women, I’m sure your “works the other way” argument may have some merit, but that isn’t what has been happening.