Disclaimer: I'll use 'post' to refer to both questions and answers. I believe the same applies for both.
So, all 'intervention' actions are ways to tell the original poster that something is not good or not good enough. The gap between not good and not good enough will likely help to define the approach.
From 'Not Good Enough' to 'WTF':
When a post is ...
In my opinion, those are all valid responses. Depends on what you mean by "dodgy". Below are some opinions about some of the related issues. I've tried to highlight the fact that these are opinions by being somewhat lighthearted.
Meta is where the culture is formed.
IMHO you've done right to ask in meta - this is where we form the culture, the norms ...
This is sort of a late answer, but I wanted to add that I oftentimes check the PMSE Notice Board for activity.
CodeGnome and Aziz hang out in there quite a bit, and we often post links to questions that we need to watch.
I'm thinking if more higher rep users in the 500+ range dropped by, it could help get those extra close votes needed to put on hold some ...
What Happened to the Spammy Posts
The two posts you referenced were addressed by the community, but insufficient action was taken by users with sufficient voting privileges. I eventually deleted those questions outright, rather than treating them as spam, for the reasons outlined in the accepted answer to a related meta question.
Flags can and ...
I've deleted the duplicate, but I can't really do more than speculate about why the flag was declined before, and offer some suggestions about how to flag this type of thing in the future.
As I currently understand it, the helpful/disputed flags are the result of actions taken (or not) by the mods, rather than something the ...