Saying that Perl was one of the first languages is silly of course. It's nowhere near as old as LISP, FORTRAN, and C.
However, Perl is the first of its kind. Prior to Perl, one would have to hack together in either Bourne or C-shell a series of commands all strung together, poorly. Grep, sed, awk, and a slew of utilities were strung together poorly with any specialized manipulations coded in and compiled from C.
Perl was the first popular language that gave us first class data structures (arrays and hashes) along with the programming structures we were familiar with in C. The inline regex support obviated the need for sed and awk gymnastics to the relief of many.
All of the crazy things in Perl that drive so many people nuts today were derived from the shell scripting that everyone was familiar with at the time. Error codes in "$!", that seems familiar, if you're used to /bin/sh. Perl's syntax which mapped shell script idioms directly into language features made these conversions a breeze.
Perl was the first and best at being able to convert these awful shell scripts into something which was maintainable. This was also Perl's primary downfall. Because it was so easy to use, lots of people who were not first-class programmers were able to write a lot of not-so-nice scripts which made later programmers sad and angry. It was a victim of its own success.
Calling it "extremely revisionist" is absurdly generous even. Calling it "one of the first" programming languages is just flat-out wrong. Lots of other languages were around for many years or even decades before: COBOL, FORTRAN, Pascal, C, Algol, LISP, just to name a few. The idea that Perl is "one of the first" is just plain insane.
