It would be helpful for the discussion if you could provide references to the studies about which you're referring.
In general, when one considers the risk/benefit balance for a product, the exposure risk needs to be considered in addition to what damage they can cause once an exposure occurs. What is the likely application of these long nanotubes, and who could potentially be exposed to them? The problem with asbestos was that it was used all over the place, in building insulation for example, and people worked with it unaware of the health risks, so not only were there occupational exposures to people who didn't know they should use protective equipment, but also exposure risks to the general public working in buildings where the material was used who would not be wearing protective equipment.
Can working with them be made safe? Are there adequate respirators to filter them from getting into the lungs? Where are they used and who could be exposed to them? Are all the applications in industrial settings where PPE can be used, or is there a consumer end-product where exposure risks are high in the general population who would not wear PPE to work with whatever the end product is? That's going to be important in determining if this is a blow to the technology in general.
Examining the studies on health risks, on the other hand, are more useful in addressing how to deal with an exposure, on the need to prevent exposure, and if there is a way to treat long-term illness in people exposed too late to mitigate early damage (if such a risk really exists...which is what I guess this thread is intended to discuss).