I got caught in a BLM movement in downtown Pittsburgh

Olivia
((Little about me I'm half white and black female and 5'10 with quite a bit of strength))
So the other day I went to downtown Pittsburgh were they had a lot of events going on. And so we are on our way to the car to go home ,but when I looked over to the T station there was a lot of African Americans coming up. And anytime there is such a large amount of people coming up from the T the first thing I think is what's going on. So we end up following them because the way they were walking was the way to the parking garage. When all of a sudden I hear screaming and cop cars. They pepper sprayed these two young girls looked 17 and 18. ((Reason unclear)) So at this point we decided to stay. We wanted to go to McDonald's before we left anyway. So we are walking that way but then I start to see swat unit cars everywhere there is literally a cop car on every corner. And I here this blonde white girl about mid twenties spouting off on a racist tangent to the cops. I do not want to repeat a single word she said it was awful. I am not a very violent person but I can tell you if tensions were not so high I would have punched her. Now to give you just a taste of the things she would say ((I'm even going to to tone it down)) "just run them over you know GTA style on the side walk officer. These dirty ((N words with hard R)) aren't worth the time of day." She went on like this for 30+ min. And when someone said something like "hey you're kind of being racist" she freaked out and asked the cop why he didn't just shoot it. YES IT SHE SAID IT. So another thing about me is sometimes loud sudden sounds can scare the hell out of me or send me into a type of sensory overload it's horrifying. So this cop that the blonde girl was talking to liked to just scare the people so if we're walking in front of his car randomly he would just do one sudden alarm. So we decided to just go home ((my sister stayed with some of her friends all white)) so I am walking I front of this cop car and he made it go off about 3 times because clearly the first time you could see how awful it was for me so he did it again and again. To see a white cop laughing just getting a horrible kick out of this. I just had to go home. 
So now this what happened as soon as we left all hell broke loose. Now my sister is still down there and I didn't find out about this till the next day. She had been tear gassed every person there had been tear gassed. The worst part is that the reason is still unclear. So at night in Pittsburgh there was going to be fireworks and the best place to see them is to go to the Point. But the problem is anyone caught in this group of people including people coming out of stores was tear gassed and not allowed to leave. So my sister is pissed but she's not going to say anything to the cops she's just going to keep her head down mouth shut and just wait it out. But you see her friends didn't understand the fact that my sister was a little scared of the cops because you don't know which ones are racist or any of that so she was just going to keep her distance. They tried taking her up to yell at the cops for not letting them go. So what my sister told me is "I guess they just don't understand fear of the cops they are white and really haven't been faced with truly cruel racism like us." Now growing up the number one rule was show respect to anyone higher than you cops and all. And to see someone rip down that rule of respect by yelling at the cops and not get pepper sprayed of hit or anything was something I never thought would happen but I guess I was seeing it from my perspective and not from someone who has not delt with Racism. 
So here is my question how do you do it how do you explain to her friends what it's like? We tried to explain it to them before but they just truly don't get it.