Im not sure who it is you are referring to as doing the deleting. Are you asking if the owners should? Or if Shrapnel should?
I think this was semi-decided back when in 2004 when another banned person went thru and deleted as many of his own programs and posts as he could find. Thats when the 30-minute edit window was reinstated, and the backups of uploaded items. The poster no longer gets those choices. Anything put on a companys server is considered to be their property.
BUT on the other hand, the users argued that the FIRST post of every thread should continue to be able to be edited. We won that back. Since most threads about mods and maps use the first post to store the link, they can be edited to point somewhere else. Anything that has been uploaded to the forum will still be there but the link would be broken. Whether or not they SHOULD be Id say no. It should be up to the author to decide, not anyone else.
By the way, the comment of "only to be sentenced to a different
boring forum" seems strange. I got the impression they had happily created that forum to prove the premise that a forum without strict moderation could be vibrant and active. I understand that there are some very entertaining threads there.