It was a predictable result of Debian policy, which Debian did not see fit to change. Debian still patches upstream sources including security-critical software, still does not have any dedicated security review of those patches, still leaves it up to individual maintainers to decide whether and how to clear these things with upstream, and still thinks all of this is fine.
> Do you think equally-bad bugs haven’t made it into upstream projects directly?
Honestly, I can't think of a single equally-bad bug in "normal" code, only in medical devices / industrial controllers / etc.. Cloudbleed wasn't this bad. Bumblebee deleting /usr wasn't this bad. It really was a uniquely awful bug.