I agree with you Brap but the poor treatment of black people wasn't related to their cock size, more their colour. Christianity considered them heathen and less godly hence the efforts to indoctrinate them. Throughout the ages cock size has been linked to virility and many races created images of the phallus. Porn has added to the obsession of cock size equaling better sex. I doubt Mina is bothered about it either but as others have said it wasn't malicious just ignorant maybe. As for the scouser thing. If we didn't recognise Harry Enfield's characterisation we wouldn't get it. My uncle was that scouser in the 80's as where many others... Stereotypes work because we recognise them on some level.
But it was part of it, it was connected to it. Itís not about intent or offence itís that itís a relic of something much deeper and more painful.