Sometimes the TGP scripts actually resolve the domain -> IP and then they have the ranges pre-programmed to a blacklist so it really depends on the TGP.
Also the reason why list owners dont like to use freehosts are several. First many freehosts redirect certain traffic to splash pages and instead of free content they get hit with a sale. Secondly, free hosts have a tendency to be a lot less stable and at times slower hence their unwillingness to list freehosts.
But if you look thru it all you can find a few decent hosts, usually the smaller ones that have been around for several months prove quite well as they haven't reached capacity yet.
Check out:
http://www.asfly.com -- good guys and make sure to have a backup of all your stuff there as well as any other host, as you never know what tomorrow could bring and you dont want your ass handed to you.