Nobody is gaslighting anyone. By your own account, the perpetrators of the looting, property damage, etc., were not part of the BLM protests, but clearly differentiated groups adding violence to something non-violent.
I live in NYC and in my neighborhood we also had windows boarded up after days of looting, cars smashed in the street, fires and more. Literally none of it was related to the BLM movement.
Similarly with Portland where many friends and coworkers live, the violence there was literally brought about by Trump and his false allocation of Homeland Security agents to “protect” federal landmarks, yet they abducted people off the street with no due process.
I’m certain looting happened, destruction happened, violence happened. It happened literally around the corner from my apartment.
That absolutely does not give anyone any entitlement to indulge racist or fascist biases to blame that violence on BLM or associate it with somehow representing the purpose of BLM, etc.