I'm not sure how any song of social comment can avoid being snobbish.

Quite easily, Dick, exactly as an essay of social comment can. It must make sufficiently clear whom and what exactly it criticizes, and mention (or clearly imply) good arguments exactly to the point. It is snobbish to attack irrelevant features of opponents and to omit argumentation, e.g. "These would-be politicians do not even know how to knot a tie!" or "These ticky-tacky lawyers send their kids to summer camps!"

Song lyricists can leave some of the work to the listener, but should make sure to set them on the right track. "Little Boxes" sends confusing signals.

There is of course more to good rhetorics, and even more to good songwriting. MR definitely had some artistic talent, but was perhaps too quick with her writing to pass the test of time completely unblemished. Of course, many others were and are worse (- yes, I am also thinking of Mudcatters, whose names I won't mention).