Somewhere in between.
Especially now that traffic is picking up, it's likely that the moderators will miss a post that needs moderating.
If we do notice a clearly problematic post, we obviously jump on it, as soon as we see it.
If we don't see it right away, we do depend a lot on flagging from other users.
We also expect a certain level of self-moderation from the community - users can either edit a bad post, or even propose and edit if they dont have enough reputation. High privileged users can also vote to close a question. (Moderators can't actually just vote like others, since their vote is automatically binding.)
There are also a lot of gray areas - such as the one you linked to. Speaking as the commenting moderator in question, my purpose was agreeing with you: it is a trivial question, as such it is a poor question. However, whether it is poor enough to close outright, or not, is as of yet undecided. For that, we're waiting for more consensus from the community.
TBH part of what tipped the scaled for me (towards undecided, and away from closing outright), was the excellent answers already received there, before I viewed the post. Closing it outright would be unfair to those fantastic posts (though, as @D.W. commented there, the question itself is unfair to the posters).
Btw, there was quite some discussion on this very issue, over at the DMZ (IT Security Chatroom). That is one way to gather consensus, and understand via discussion the different issues at hand.
Feel free to jump in!
P.S. I also want to point you at this blogpost from @JeffA, while this pertains to all of SE, we do also try to follow those guidelines.