Why 'HYIP' isn't going to be removed is fairly complex question to which I can't provide an answer to. IIRC sometime in the past this section didn't exist.
Wasn't the section added in the past to shift the HYIP and ponzi threads from the gambling section (or other sections for that matter) to a single section to prevent newbies from falling for it? (Well, they still do, of course, but the section prevents the gates from being breached by barrages of threads)
Unless I'm wrong. Can a bitcointalk historian clarify?