I read this as well. It's probably my lack of contact with 'black' people that leads to me still being ignorant of the potentially offensive nature of the word 'coloured'. The BBC article refers to the term being in common usage until the 1970's. I would go further than that. In the 1980's and 90's, I am fairly sure that using 'coloured' to describe 'black' people was still the 'correct' term. I am now 47, and I can't help feel that 'black' is actually the offensive term ! Again, looks like my ignorance of the issues.
Notice as well that the actor boy using the term would be 'coloured' as opposed to 'colored' - the US term, and he was giving the interview in the US media. Right enough, historically, you can see evidence of a time when signs would read 'no coloreds' so understand now the reason it's the way it is over there.
Thing is, who decides what terms are ok or not ?
I'm with you - coloured was definitely the preferred term when I was going up. I still cringe using the word 'black' when referring to someone because it was drummed into me that it was the wrong thing to say.