"a fantastic language to slice, clean up, and extract information from text files, and it was already very widely used in bioinformatics" is a description of Perl 5, not Perl 6.
Even if Perl 6 is completed, I don't think it is a practical workhorse for many real world situations.
To me being able to create grammars in Perl 6 to parse text data sounds really compelling. However, every time I have played around with them, Perl 6 has been so slow, that I have reverted to using regular expressions in another language.
I'm pretty sure GP is referring to Perl 5, not the newly renamed Raku. Perl 5 had a lot of use in bioinformatics, and to my knowledge lasted quite a while after the general Perl exodus, until eventually being replaced by biopython.
If the confusion regarding Perl 5/6 never happened, it might have retained that popularity in that domain.