There is an open protocol[1] on how to retrieve the certificates, so you can implement a client in a language of your choice, or wait until someone else does it.
That comment was about package management (i.e. actually installing this on servers), not about language implementations. Let's Encrypt's documentation currently assumes a Debian-based operating system, which therefore leaves out a very large portion of the web server population.
[1]: https://github.com/letsencrypt/acme-spec