well, with the slack of hosting DC++ on th site, and not hosting the source files, i do not think the owners want to host too many GPL'd software titles on the site, as they would need to also make room for every version's source code, this ofcourse depends on the licensing of those which you mentioned, of which i am unaware of.
Do to the nature of the GPL and its insistance on hosting binaries and source files, it can eat up alot of space. many of the programs hosted on Sourceforge also host their older verisons +source, so it might be simpler just to point someone to these sistes.
If the programs are not under GPL, then maybe they will consider it. It would be nicer if they were licensed under a BSD license, then one is not required to host the source files alongside binaries.