1 - I am a blonde-haired, blue-eyed, white male who until recently identified as a straight male. Nobody's discriminating against me. I am not a person of colour, I am not a woman, and like I said until recently I was not a member of the LGBT community (Well, not openly, anyway.) Nobody's discriminating against me in a way that has any effect.
2 - a racism is just a cheeky way to describe an act of racism. IE: Nobody's shooting me in the back or targetting me for my skin colour or gender.
3 - I think you're misrepresenting the data, more than anything else. You're misassociating. Supporting BLM and being a shitty person are not mutually exclusive, nor are they intrinsically linked. I am not saying someone who supports BLM is incapable of being a bad person or targeting your friend's business, and I'm not saying they're definitely a supporter or not. Those things are not related. I am saying that, given BLM's goals during all this, that rioting and vandalizing and looting are counterproductive to their cause. The more likely explanation is that these people were opportunists using the protests as an excuse to loot and plunder. They might even be hardcore supporters of BLM, but if that's the case then their act here is not a part of BLM's goals and thus they shouldn't represent the movement in your eyes.
I don't think you should judge BLM or misrepresent their goals based on what a handful of folks did to your friend. Correlation is not causation, and looting is an unfortunate side effect when any large-scale protest happens.
I don't believe either that only peaceful protests can bring about change. At the very least an act of defiance is needed to start the road to change and protesting in designated protest areas isn't it.
However: "I am saying that, given BLM's goals during all this, that rioting and vandalizing and looting are counterproductive to their cause" You are contradicting yourself, promoting violent resistance while saying it's counter productive.
There is a difference between acts of defiance and violent protests. Look at the Gaza strip, violence isn't getting them anywhere. Any act of defiance garnering them outside pressure on Israel, is eroded again by continuing acts of violence, keeping the status quo in place.
Blockades can be effective, random violence never is. Block major road arteries away from city centers, that will vastly reduce the chance of looters taking advantage as well.