Why is this list called Perl best practices? Only 7, 11, 20 and maybe 18 is related to Perl. The rest is valid for any language.

They're all related to perl since perl is a programming language :)

Perhaps you meant specific to perl ?

But even if they look specific, they all really are generic

7. Perl is a powerful and expressive language, don't be afraid to use it to its maximum.

write idiomatic code

11. Don't use an object when a simple hash or array will do.

Don't use an object when a simple struct will do

Don't use an object when a simple data structure will do

20. use strict, use warnings, selectively disable them when required.

lint that mother hard, maximum warnings -Wall

lint, "use strict";

18. Add lots of debugging code

use assertions, use logging