But when that many people die, in that many separate incidents, across a variety of nations & launch vehicles - then the "The risk of spaceflight is still very high" thesis is statistically solid.
To what extent is that true when the cause of the fatalities is the technical design of completely unrelated systems?
If one space agency built a rocket which always immediately exploded after launch, and another space agency built one which always worked, you could say the odds of failure for the next astronaut was 50%. But of course the two rockets are essentially unrelated. The chance of success of each rocket is a function of design, engineering process, organisational culture of that organisation.
Telling the astronaut strapped to the top of the explody rocket that there's a 50% chance of exploding is actually less help than no estimate. Because actually there's a 100% chance of them exploding. An estimate is only as valuable as the assumptions that drive it.
But when that many people die, in that many separate incidents, across a variety of nations & launch vehicles - then the "The risk of spaceflight is still very high" thesis is statistically solid.