Yes, normal perl code can sometimes become unreadable for those who don't use perl regularly. But isn't it the same with other programming languages?

APL is infamously hard to read for outsiders, even more than perl. Lisp or Scheme code is reported to be difficult to read for those who're not used to it.

Even some bash code like

# bash functions for manipulating the path

shopt -s extglob

# addpath appends a directory to the path unless it is already there
# eg: addpath ~/bin
addpath(){
local a p=":$PATH:"; for a;
do case "$p" in (*:"${a%/}"?(/):*);; (*) p="$p$a:";; esac;
done; p="${p#:}"; PATH="${p%:}";
}

# delpath deletes a dir from the path
delpath(){
local a p=":$PATH:"; for a;
do a="${a%/}"; p=${p/:"${a}"?(\/):/:};
done; p="${p#:}"; PATH="${p%:}";
}

#END
[download]

can be impossible to read (I've written this as normal code, not intentionally obfuscated), and even C++ code can get very ugly.