Based on what logic?

Laziness (mainly), impatience, and hubris — along with a good dose of πιστις, ελπις, and αγαπη.

Anyway, I expect that if/when ζ catches on, there will spring up a new community site devoted to it and so the question here will become moot.

Will all projects/languages inspired by Perl be equally welcome

I don't know about "inspired by", because, after all, that would include PHP and Ruby. :-P

I think if a project is based on Perl (say, a new dialect someone is working on, like Perl11) then questions about it would be allowed here.

It's worth noting that there is a significant grey area between allowed and welcome. A post on Perl11 would be allowed, but the poster might find it not very warmly received. That's ok. We have ways of handling content in the grey area. Posts can have their titles prefixed with "(OT)", or posts can be moved to the "offtopic ghetto", like what was done with this post. I think the admins would like to leave these decisions to the moderators. What we don't want is for any action on a "Perl 6" post other than reap to incite some members to launch yet another crusade against P6 here. If you don't like it, scroll past.