"I think what's most damaging to Perl is commentary like what the OP quoted. Unfortunately, I don't know how to counter it."
I think one solution is to continuously hack the planet with excellent must-have software written in Perl! It doesn't even have to be complicated. As the ultimate glue language Perl has an infinite number of potentialities.
For example Perl is installed by default on OSX and Linux. Both of these operating systems have around 2000 command line programs. Few Mac users know what lurks beneath the desktop. Perl can expose this power by wrapping and combining system commands and canning complex syntax to invent new commands that make hard things easy.
Fortunately packaging Perl programs for cross-platform distribution has never been easier!
$0.02