This came about mostly through inertia, as that's just what was easy after making sure that we weren't placing enough autoflags (4) to auto-delete posts. There was a bit of choice to stay at 3 autoflags, rather than go to 2 or 3, but it was at least somewhat more work to get there. It's been over a year, now, since the change. People have, mostly, felt it's going well. The one primary objector,
Science Fiction & Fantasy, has been handled by setting their site to get a maximum of 2 autoflags.