I think there's too much obsession about the fatal accident.
As said before there are simply not enough fatal accidents to make a reliable statistics on. For an accident to be fatal it has to be a rather spectacular one such as the ones agbd mentions above. Most accidents don't actually have a fatal outcome unless it's a high speed accident such as loss of control or CFIT, or there might be the odd case of very unlycky circumstances making the survival prospects very small. An engine failure daytime, even if caused by gross negligence, is normally a very survivable accident. And the most frequent accidents are very rarely fatal. Such as the mishandled crosswind landing, or the continued landing in to a wet short grass strip with too much speed, etc.
A few years ago (in the 90's) there was a survey regarding accident rates with gliders but it did not focus on fatalities, but all accidents. Compared to the large variety of different private flying operations, gliding is somewhat more consistent. Most of the flights takes place in similar weather conditions, similar type of flying, not too much variety of aircraft complexitiy and performance. (Mountain flying was excluded). The conclusion was quite similar to the "Killing Zone", that there was an increased rate of accidents at a certain level of experience. But once again, this was statistics which could be questioned just as we have done here.