These statutes was not famous for being slave traders. In fact blacks people owned white slaves in Barbary. 

William Beckford was famous for being English novelist a art collector, patron of works of decorative art, a critic, travel writer,politician and at one stage in his life to was richest commoner in England.

Sir John Cass was famous for being a English merchant, member of parliament and philanthropist.

Cecil John Rhodes was famous for being a British-African mining magnate, politician in southern Africa who served as Prime Minister.

History is not there for you to like or dislike, it is there for you to learn from it,and if it offends you' even better because you are less likely to repeat it' it's not yours to erase or destroy, it belongs to all of us.

If you're offended by a statue see a therapist says Esther Krakue.

Even people of colour are happy for the statutes to be up and the statues benefits travel and tourism.