Because Parrot isn't a Perl 6 component. The idea is that it's a dynamic-language-neutral VM, which happens to support features of Perl 6. Perl 6 (via Pugs) was being impelemented sans Parrot for quite some time, and even now, it's only one possible backend target for Pugs.
Ponie also isn't a Perl 6 component. It's Perl 5 on Parrot. (I know you didn't outright say that Ponie is a Perl 6 component, but it's position in your "dialogue" seemed to imply that impression.)
As for why name releases, I suppose part of it could be just an opportunity to be clever, but most of it is probably because most people remember names better than numbers.
