Basically, in the hands of incompetent programmers, everything is unreadable. If you are disciplined, you can write easily-readable Perl. I (and my coworkers) do it every day.
Oh, one other thing... the linked article is from 2000. In the last 8 years, the Perl community has figured out how to program... so most of his points aren't relevant anymore. Nobody writes 2000-style Perl anymore.