Its still in the works but coming soon - but practically there's an upcoming, new spam prevention mechanism that should help somewhat independently cast a final flag. This wasn't public (and I'm hazy if I was aware of these plans) at the initial time of posting and has no baring on our decision. It should let automated systems handle the worst of it
I also asked about statistics from the community department - there's quite a bit there (mostly pretty good!) but critically (and I asked for permission to share)
To summarize in a handy way: Since Nov 2024, a majority of spam posts on Super User are removed within 2 minutes of posting. Going by the weekly breakdown, that mark is currently at about 3 minutes and has been hovering around there since late March.
Which isn't half bad ;)