Thanks for the link, that is interesting. While I don't doubt that it's possible to create something similar to https://github.com/weavejester/hiccup in Ruby and Python as well, I am not aware of existing libraries for it and it's definitely not considered the "idiomatic" way to generate HTML in those languages. They both skew heavily toward template languages that are some variation on <div>{{foo.bar}}</div> and require special syntax, which in turn requires editor support for syntax highlighting and such. And Javascript has been the same way until recently--Angular and Ember are template-based by default. And while JSML looks pretty good, I think the other alternative Javascript is trending toward is the JSX approach taken by React, which is basically just backwards templating, and requires a precompiler pass.

Meanwhile with Clojure, because it's homoiconic (code is data and data is code), all you need to implement a DSL for generating HTML is basic functions and macros (which are just functions that process your source code), no special new syntax is necessary. In fact if browsers used Clojure (or any other Lisp/Scheme dialect) as their native scripting language, there'd be no reason for HTML, XML, JSON, or CSS to exist at all in the first place. They could all just be code.