He was anticipating the argument that succinctness leads to unreadable code. Perl is a language where you can choose to be so terse as to be nearly unreadable.
I don't think he was trying to claim that was idiomatic perl. Rather he was saying that clojure is succinct and still very readable.
If he chose his example without consideration of idiomatic Perl, then his attempt appears even worse. Further he chose to remove all spaces from the example, presumably to demonstrate that Perl code is "not clear".
I have not written a single line of clojure, and don't know how idiomatic clojure looks like. I tried to translate his example to clojure using my very limited knowledge and looking at the examples on ClojureDocs site:
I am sure this is not idiomatic clojure, and probably a very bad way to write. If I cited this as an example of typical clojure code, then I'd be making a totally unfair judgment.
The funny thing is, when I just add spaces to the Perl code segment, it looks quite readable to me. But then, I probably know more Perl than him.
I did not paste the Clojure example from anywhere. I wrote it. It was not intentional on my part to write broken code, but if it was, it actually nicely illustrates my point.
"He was anticipating the argument that succinctness leads to unreadable code"
And it's a valid argument. There's sometimes a tradeoff between terseness and readability. Of course, readability suffers if the code gets too verbose as well.. go figure.
"Perl is a language where you can choose to be so terse as to be nearly unreadable"
You can actually choose a "level" of succinctness that fits the task at hand and your personal style. This is a very cool feature of Perl that it should be praised for. I agree with GP that the OP intentionally misrepresents it.
I don't think he was trying to claim that was idiomatic perl. Rather he was saying that clojure is succinct and still very readable.