Can't say it was a "few isolated morons" MB. Thats more like nowadays. Beck then it was endemic. The swing low song did come from the Twickenham crowd in '88 towards a black player, so I'm.not sure English RL was any better than English RU regards race relations.
The more obvious example of racism in the RU hierarchy was in South Africa. The 'white mans game' was the sporting wing of apartheid, the consequences of which are still in effect today (regardless of Mandela's incredible gesture). Most black South Africans couldn't care less about Rugby.
Endemic among a few isolated morons. British RL had a black captain in 72.