I am genuinely sorry for, and appalled by any abuse you have received. I have some Jewish and black heritage, although it is far enough back that it is not apparent. My mum and her mum were on the receiving end of abuse for the black heritage.
However, anyone claiming to be left wing and dishing out any kind of hate speech does not belong on the left. If they say they are then they are wrong by definition, with one of the founding principles of Socialism being equality.