It is known as brigading. They see a post critical of police and the right wing people come in and do a bunch of posts to obscure the fact that BLM and the police accountability movement is extremely popular.

It is 100% planned and engineered. They know their talking points. They know what to point to in response to police accountability discussions. Change the subject to talk about random looters instead of the 99% of protestors who peacefully assemble and then are brutalized night over night.