(S)he'll just quote different sources supporting her argument, all from politically motivated bodies. Your sources will never be good enough.
My advice is to let them scream in the wind and think they've scored points somehow. They'll figure it out by 40 or continue to be someone's useful idiot.
The second one is somewhat laughable in my opinion: The researcher dismisses the possibility of being a subject of the study tempering reaction times out of hand. That's ridiculous. Everyone is aware that race is a critical factor in this sort of survey, and to not even consider it as a factor in decision-making under made-up circumstances, where one's behavior is being constantly monitored is simply ludicrous.
As for black policemen also being more likely to shoot at black men: Yes! The problem of racism is systemic. Black men growing up in our system will also imbibe the lesson that other black men are dangerous. I don't see how this contradicts anything.
Well, that's the magic of social "sciences", you may dismiss all data as much as you want in order to fit your pre conceived ideas. So I must actually agree with the OP here: is a waste of time to give you facts about this since you are always going to find a way to dismiss them.
Edit: To be more precise, on a regular basis one reads reports of black people getting entangled in situations where law enforcement escalates an encounter into violence and/or death, or where the officer involved gets away without legal consequences for initiating such escalation. Does this happen just as regularly with other races? If so, where is the reportage? Is it being deliberately ignored by the media? Nothing you linked addresses this.