Horst H. von Brand wrote:
"corrupts data"
Could we add "X starts, but only shows a blank screen; no keyboard or mouse response"? (Happened to me yesterday after the updates from the day before, haven't had time to corroborate)
That one is almost certainly "no". If there was a steadfast rule that if X failed for any user, it would block a Fedora release, then there would never ever be another Fedora release ever period.
Every release of X will categorically fail not just for one user, but for multitudes of users due to the complexity of the software compared to the number of developers working on it. Any large software project as complicated as X, the kernel, firefox, apache, etc. will always have a multitude of bugs in them by very nature of their size and complexity.
Only bugs involving data loss or widespread catastrophic problems for multitudes of users should "block" a release if the release is ever to go out the door.
This is where the "would be nice if" ideology and the "this is what happens in the real world under $constraints" realities diverge greatly.