Well, by themselves the Singapore data might not indicate that much. But we also have the evidence of where SARS continues to spread, and where it has petered out.
I'm not sure where you have seen it "peter out". Hong Kong is down to single digits in new cases and may have it under control. But that, through heroic efforts, not a "petering out".
The only outbreak we have seen in a multi-ethnic society is the one in Toronto, and I've seen no ethnic breakdown on the victims. Have you?