No it's not. Speed is a very significant element of road safety. At lower speeds, you can stop in a much shorter distance, and if you hit someone their chance of death or serious injury goes way down. Braking distance is proportional to the square of velocity, and reaction distance is directly proportional. If hit at 50 km/h, a pedestrian has a 90% chance of death. At 30 km/h, they have a 90% chance of survival.

At lower speeds, you're also far more likely to notice something that might require you to stop or slow. Your cone of vision at 60 km/h is 40°. At 80 it's 30°, and at 100 km/h it's 20°. A different source I found says under 50 km/h it's 104° and at 65 it's 70°. Whatever the specifics, lower speeds are much safer.

This isn't to say that speed cameras are the best or should be the only method used to ensure road safety. Narrowing roads, adding furniture by the roadside, and increasing the complexity of the route, are all good ways to reinforce a lower speed limit by reducing how safe drivers feel driving at high speed. But speed cameras are a useful supplement to that, for those drivers determined to be irresponsible.

Both risk of collision as well as risk of injury / death if a collision occurs correlate heavily with speed, there's literally no better factor than speed to consider. Of course, it's not the only factor, that's why we have safety and license requirements for vehicles and drivers as well.