Well, the implication to me atleast was that the blight is somekind of alternative reality that the DO imposes on the actual real reality, and as his power fluctuates, the blight does too. That is why we have scenes where the blight retreats and there is healthy ground underneath when it happens. And apparently since this DO-reality is unnatural and not something the creator intended to exist, it does not have a reflection in TAR.

So yes, RJ did not specifically deny the idea that SG itself is somehow not in the blight, but I think thats stretching it. I think if anything, SG and the area around it are even MORE "blighted" since they are so close to the bore and the source of the DO's power.