I declined the flag, precisely because it is on-topic here.
Typically if a post is cross-posted to multiple sites, it should be closed on the sites on which it is _not_ on-topic. I'm a bit surprised that it wasn't closed on SO; that's not a topic I usually expect to see left open there. (But the presence of the bounty prevents people from voting to close it.)
There's more, in this particular case; I asked the OP to clarify his question, but he never came back to do so. If _he_ wanted it closed, for whatever reason, I'd be much more inclined to do so. And if he doesn't do so soon, I might close it anyway.