I instantly know whether someone is black. I don’t instantly know if someone is a Jew on appearance.
Even if I did “know” someone to be a Jew it would mean nothing to me any more than if they said they were a Catholic or indeed an Atheist.
It is to do with what brand of useless nonsense our heads were filled with when growing up.
I never understood the fascination and prejudice with red hair either. Just like the fuss made over very blonde hair.
It is just a colouring. It is just silly.
Travellers are more of a prominent issue nowdays whereas Gypsies were the thing of fairy tales when I was a child.
Many people just ape what their parents said about them even if they are largely unaffected on a day to day basis by travelling communities. It is more political than personal.
Being black however brings with it a host of possibilities for prejudice because of the long history of black people being abused and vilified by white people.
Some is overt racism some more subtle, some is undoubtedly “built in” to our politics, education, policing,Royal family, western churches.
So in that way I do understand what Diane Abbot is saying.
There is a level of sheer hatred that is spouted by the extreme racist in our society that is directed at black people that is only in my opinion matched by extreme misogynists such as those known as incels.