Whether or not this is good advice entirely depends on what someone wants to do. Advantages of Perl include CPAN, widespread availability of good help, and more mindshare. My view is that Python and Perl are about equal on quality but appeal to different personalities. Python also doesn't have CPAN, and doesn't have the same mindshare. Ruby is hands down a better designed language than either Perl or Python, but is so far below critical mass in English-speaking areas that it isn't funny.

Which means that for an infrequent programmer, Perl is better. They can get stuff done, using convenient CPAN modules and with lots of useful assistance. Choosing modules can be confusing, but they can ask somewhere like here. For a more frequent programmer, well if you tackle lots of different things, then CPAN pays off again, and again, and again. A better language only beats a better library if the language is quite a bit better, you are better and library design than the library author, and you can amortize the cost of writing that library over a lot of further work. You will note that Paul Graham used Common Lisp (in his opinion a much better language) for the core stuff, and then Perl for all of the random bits that needed to get done but not built on (like email).

Oh, and the demise of Perl 5 is often predicted and has yet to come true. The truth is that Perl 6 is unlikely to be released for a good time yet, and after it is, the differences are such that Perl 5 will continue to grow on a separate trajectory. Therefore the possibility of Perl 6 on the horizon shouldn't dissuade people from learning Perl 5 one bit.