There hasn't been a single failure of a reused falcon 9 booster on launch, which is the bit relevant to human spaceflight. Humans aren't going to ride a falcon 9 down to landing.

If you're talking about starship then I'm not sure how worthwhile extrapolating from F9 is. I would guess they're pushing F9 to its limits here - after all a small gain in launch efficiency multiplied by the size of the StarLink constellation is a big overall improvement!

This comment is nonsensical.

Just like anything else, assuming SpaceX is able to build a functioning example of their Starship concept, they'll fly demonstration flights and iterate on the design and perform safety analyses until they're satisfied that it meets (at least) industry-standard safety margins (or until they see that it can't). I don't understand what you (apparently) think is fundamentally different about this particular technology vs. all the other machines humans put their trust in that are theoretically capable of killing them if something goes wrong.

Nobody is trying to land humans on the reusable part of the rocket, this is the first stage returning under power. There is no elephant in the room, there is no room and no elephant either, so a lack of data is the expectation, not something worth mentioning.

Not sure if you're being serious or not, but the Shuttle was reusable (or at least, the part that carried the crew was).

There was no publicly available data that pointed humans can safely go to space and return inside a cannonball, eject and land via parachute yet Gagarin did just that.

Every new step in space race was pushing the limits of what was thought possible. Of course no one will take on these type of risks today but with enough testing the risk can be reduced and mitigated.

This is what it looks like to be part way along the path to human safety.

There is a ton of work ahead, but we are going in the right direction.