Saying there are no s-expression parsers for non-Lisp is ridiculous.
This one's http://sexpr.sourceforge.net/ for C, it's been in sourceforge since 2002.
perhaps you prefer one in :
Javascript - http://planet.plt-scheme.org/package-source/dherman/javascri...
Perl - http://search.cpan.org/~nelhage/Data-SExpression-0.34/lib/Da...
Limbo - http://man.cat-v.org/inferno/6/sexprs
I shan't go on
But you'll note the disparity in support. A library for parsing XML with C may have existed since 2002, but it's existed for XML since 97. In Java, XML support has been baked into the JVM for a while, but S-exp parsers are hard to find. That library you list for Javascript is not a s-exp parser but rather a Scheme library for generating Javascript from a Scheme-like language. Googling for javascript and s-exps returns a lot of results like that but not many s-expression parsers. There certainly aren't any widely used and recognized libraries like there are for XML and JSON fro most languages aside from Lisp.