Even a charitable reading suggests this is a racist post. In one swoop, Dandydan has managed to label all black people as the same, thereby delegitimizing their own individual identity (this is a common racist tactic: e.g., "all black people act the same; they are all "activists"; they are all thugs etc.) and then inverts this labeling by suggesting that some criminal black men are part of the very justice-oriented movement that seeks to rectify systematic racism. I see this all the time on the neo-nazi, white supremacist website stormfront.org; I believe it originated as a meme on the virulently racist
Daily Stormer (links to wikipedia). Or you can click on this google image search link
here (links to google image search page using "racist meme" "black lives matter" as search terms).