No Shine, I did NOT say that high speeds are safe. That was not my point at all. My point is that it is what I'd call "relative speed" that makes a difference. If the majority of traffic is plodding along at 50 mph, and one vehicle trying to blast through the pack at 80 mph, the "fast" car is an extreme hazard to everyone, including himself (assuming the usual way this is done, weaving in and out, and so forth). It is far safer for everyone if all (or a large majority) of the cars on the road are traveling at similar speeds.
You also mistakenly assumed that I was implying that speed is somehow a dominant factor in overall safety. Again, I didn't say that either. Speed, or relative speed, is but one of many, many factors that will determine the probability of an unsafe event taking place. Traffic density is another factor, as would be condition of road surface, weather conditions, wind, temperature, and so forth.