You might well believe McTernan is talking nonsense, but believe me he's merely articulating mainstream Labour thinking and this has been Labour's view for decades, once you realise that, then the debate about two tier policing is a moot point. For Daubney this was political protest that got out of hand, but for McTernan this was racist perpetrators versus ethnic minority victims, there's no immunity for those who stand and watch, they're accessories to a crime, a racist riot and they're all culpable.
Your politics and mine are not aligned, but on this issue I profoundly disagree with Labour, it is not racist to be a nativist, it is not racist to believe in a mainstream British culture. Racism is a belief in racial superiority and inferiority, it's only in the last couple of decades that racism has ballooned to encompass nativism and immigration.