I am not whining, just wondering
Bill the Lizard moved it with his witchcraft, but I suspect it was because it isn't really about programming. It's asking for a plugin for his blog; not how to design a plugin, not how to work with the API of a plugin, not how to import a plugin into his custom blog software.
It's a judgement call, and anytime it's close it's going to end up on the more general site because it only takes 5 users who favor that site to push it there.
That said, in this case I suspect it's because it's not talking about writing or changing any new code, but just looking to setup or configure something that's already written.
Curious; I probably wouldn't have migrated that, but it is sometimes a tricky call. You'd be surprised how odd things get; I had a moderator flag earlier asking (quite correctly) for a moderator to save a SO post about using linux on a laptop from going to SF, when it is clearly SU material (it was 1 vote away from SF).