It's because he views user data integrity as a more critical concern than the PR process or team dynamics - which, as a user, I don't fault him for. I think that in his mind, every hour/day/week spent debating things on a PR equals more people losing or corrupting data. This is not commonly the case with most PRs - it's specific to popular filesystems in active development.
What I don't necessarily buy is how to weigh this responsibility against the responsibility users take on when they use such an experimental FS in the first place. It's a tough question in my mind, and both sides have good points. And I also don't know anything about the relative safety vs. severity of each patch. But what I do understand is the motivation for not viewing these as generic PRs against generic codebases. So the idea that this is a red flag in this case just doesn't seem right to me, based on my current understanding.