Except the racists, as they were true racists, are not the traditional shaven headed white assholes. They are the other racists that the left does not want to admit exist.
It is at this point that I feel impelled to make the distinction that original white working class skinheads were not racists. The traditional skinhead "Trojan" movement was built around reggae, ska, and soul; they all bopped around to Desmond Dekker.
Shaven-headed, white power, knob-head, "Romper stompers" were more commonly known as "boneheads."
Now my defence of original skinheads is over ... 
.. it is noticeable in my region that the most horrendous physical attacks upon asylum seekers over the last ten years have been from people of other minority groups. We had a Kurdish lad who was left brain-damaged after a street attack, and the reason given was that, as a Kurd, he must be "anti-Saddam".
We've also had street violence issues between EU migrant communities and other minority communities.
Unfortunately, Diane Abbott is very much stuck in an old paradigm of British racial tension that very much dates to the 70s and 80s, and this clouds her ability to see the actual situation on the ground in 2017.