I think it's more that the syntax is fairly similar to HTML already. HTML is basically deeply nested lists with some attributes attached to the nodes, and lisp code is deeply nested lists with keywords replacing attributes.

That is to say Clojure/lisp programmers are likely more familiar working with deeply nested lists of data.

You could write a very similar library in Python if you wanted using lists, I'm just doubtful anyone would use it because it's not "Pythonic".