Not parent and I also consider R to be a surprisingly solid general purpose PL but the one reason that I can think of is that formulas are part of the language. Formulas are extremely well-suited for data analysis but odd outside of that.
Of course that doesn't make it a DSL. It simply means that R was designed with a particular application in mind. So was Perl (regular expressions as first-class citizens) or Javascript (DOM manipulation). Not to mention PHP.