Other than the fact that yeah, the MSM will put it all on "right wing extremists", I'm not sure I have a problem with cops standing back as two groups like that fight. As long as no innocents are hurt, I'm kinda "meh".
The cops and antifa work for the same ahole politicians. The cops were told to not go there so their cohorts in Antifa could do the political violence that was desired by the politicians.