They give this guy a negative DT rating but don't bother with confronting the lazy campaign manager that is enabling this spam to go on. That doesn't make sense to me.
False assumption. I've been contacting several managers and campaigns regarding this issues. Some of us are also working on another method of combating spam.
The problem here is if she felt he was spamming so badly that he deserves a negative rating then why didn't she delete his spam?
I can't delete it. Even if I could, it would have little effect. It is pretty impossible to clean up after every spammer.
In addition as I am curious, did this user receive any sort of warning beforehand about his behavior? I've been found guilty of spam myself but staff didn't come at me with negative trust they simply deleted the posts they considered spam from different threads.
No. This isn't an action from a staff member, but rather a member of the default trust system. Those are not necessarily connected.
P.S. Look at the findings from rizzarolla.