I find that what many people actually mean isPerl 6 is not the next version of Perl 5
Which is right, of course.
Well, duh, that the latter is true is bloody obvious. Perl 5.10 isn't the next version of Perl 5.8 either.
I can't talk for the people you've engaged in discussion, but when I say that I think "Perl 6 isn't the next version of Perl", I mean it in the same way as if I say that I don't think that "Kurilla isn't the next version of Perl". Nor have I considered Ruby to be a version of Perl ('next', 'different', '...').
Still I can see why many Perl 5 programmers fear
Fear? Noone was talking about fear. And the people I talk to, don't fear Perl 6. Just as they don't fear Ruby. Of Java. Or C. Or any other existing or emerging language.
It's a bit cheap to dismiss people who refuse to drink the Perl 6 Kool-Aid as being fearful.