I think it was to attack those who had not been given the SARS vaccine. But when it got out, it was worse on those people.
All rumor, and I would be careful with how much that is believed.
It seems I read a few years back that the more people catch a virus, the more likely it is to adapt. So, for example, even if the virus is more virulent in Asians now, (and the one study with the 8 samples is pretty weak, maybe there are others out there now), the more it infects people of other races, the more likely it is to adapt. Of course, after a while, it can become less virulent too, but I’m not seeing that so far!
Possible, I suppose.
And indeed we don’t really know anything on this. It is all reports of reports.