I'm not sure I'd regard that as intentioanlly racist.
Stereotyping, yes, but most of us do that on a regualr basis without even realising it.
While it may be politically more accurate, I'm not sure that "adopting a filipino, chinese, indian, african or otherwise underpriveleged boy to clean the chimneys" would be any more acceptable, and certainly not dramatically effective, or reflective of how people generally speak.
NB - I havent yet seen the program but will hopefully watch it tomorrow on iplayer - I quite like Torchwood normally.