Perl was a gazillion times more powerful than Bourne and C-shell (including all the Unix shell tools like `awk`), much more rapid than working in C, incredibly terse (perhaps too much so), and also portable (to all the oddball systems you might have).
And the purposes to which Perl was put were often to automate things you'd been doing manually, or that you couldn't do without Perl.
You'd be quietly doing big things with Perl. And there were sayings about how you'd automated your job, and presumably spent your time writing more Perl scripts and reading Usenet. And the occasional joke of replacing someone else with a one-line Perl script.
Also, note that not only was this before the dotcom boom (when programmers suddenly were no longer nerds but getting rich and fashionable), but also-- a lot of the programmers using Perl professionally weren't even professional programmers, but actually sysadmins or random university researchers, who happened to have the power of Perl. The majority of professional programmers on Unix actually didn't know Perl.
So, Perl people speaking of Perl people in terms of vices could be seen as a self-deprecating, joking spin conscious of the unusual power that they wielded.