the observation that people with African ancestry are visually more easily identified in everyday life than Jews seems like a perfectly reasonable comment to me - well, it depends what kind of Jews we're talking about. Hasidic Jews are just as visible as African-Americans.
But, yes, Jews often look like Europeans, and often even have partial European ancestry and so 'blend in' better than others.
But, again, it's when she said that 'Jews can't experience racism, only prejudice like red-heads' is when the insanity kicks in.
Hitler killed millions of Jews because he believed them to be racially inferior - fact.
Here's a thought experiment: imagine that you are Jewish, and live in a Jewish enclave of Manchester or London. The Jewish cemetery has been wrecked by vandals - some head stones have been smashed and a swastika has been daubed on one of them. The local synagogue has to have bars on the windows and security. Maybe one or two of your relatives were killed in the holocaust. Corbyn was kicked out of Labour for saying the anti-Semitism issue was blown way out of proportion. And now Diane Abbot lets slip what she thinks about Jews and racism.
How would you feel?