That's how the media and government will frame peaceful protests and marches as violent riots and taint the cause.
If you attended those event you'll be blamed for it and will face the consequences -- you'll lose your job, or get kicked off planes, get banned off social media.
Inversely, if antifa and BLM carry out a violent riot, they'll say it was mostly peaceful and that the violence was caused by right wing infiltrators.
They WILL blame you for their violence.
Up is down. Left is right. Black is white.
They have the power to distort peoples perception of reality itself.
theres always a risk of bad actors. Im not sure that should keep everyone from protesting.