I want to have the modules that I created and put onto CPAN in a "anybody can contribute" mode, but CPAN won't even allow me to do that.

This is confused. CPAN is the Comprehensive Perl Archive Network and is well named (Ha, how I hope I am not walking into another backronym. ). If you have the right, you can develop a codebase where, how, and with whom you like, then you can release it on CPAN.

Licenses, established practice, and courtesy are arguments against summarily grabbing some author's code off of CPAN, reworking it, and putting it back on CPAN under the same name. It is not surprising that the CPAN admins are slow to declare code abandoned and then seize it.

Be well,
rir