You can report the posts of the user you mentioned for the mods to delete his posts and possibly ban him for spam, too.
That is not the problem. The problem is that the newbies / most other users would believe that the remaining 1 page is "scam free". They would then not even take any basic precautions while dealing with these announcements.
There would be no problem on the forum's part by then, but that would be the newbies who wouldn't do any further research. The most basic response of someone who has been scammed is to find other people to blame when they literally haven't made anything to protect themselves from being a victim.
My point is that there isn't a need to delete threads that are related to scams. The mods are fully aware of the situation. You can cast -ve to people who scammed others so that other members would somehoe be guided. If you still get scammed by the same people, don't look for someone else to blame.