If you come across a post which is obviously a SPAM post, like this one. Is it a common use to edit the question like
"content removed due to spam restrictions"
or is this a job for moderators and is our job limited to flagging this post?
The moderators exist to expedite handling of things that most people would close or edit.
In the case of obvious spamming, attention grabs - flagging is often the best way to not encourage bad behavior by bumping something up on the active queue.
When something is so clearly harmful or spam, it's OK to edit if you are improving things - but generally a vote to close or a flag is the best choice.
In the case you linked to - the close vote, downvote and flag would be the actions I would take. No need to edit it to make it look better or less threatening - just close, flag and move on.
We encourage community editing for making things better - so that's always acceptable if your motive is good - but sometimes you can't "polish a turd" and end up spreading it when it needs someone with the right tools to properly dispose of a post.