Here's a link for the black-listed writer, Carl Foreman, who did the screenplay:
http://www.imdb.com/name/nm0286025/bio
I haven't seen it, but there was a PBS show about the squabble between Foreman and
another crew-member about the writing credits for the film.
Even if the writer intended a McCarthy-writers allegory, I always saw it as being like
a Bugs Bunny cartoon: it works on a number of levels.
It's a decent Western, it's a bit of a love story, it says something about locale
control (the comment by one character about the folks in the state capitol not
understanding how things worked in their town), and even a Cold-War of the USA and a very
few friends staying the course against the tough Communists.
I suppose that poses something of an ethical dilemma: Are we allowed to enjoy marxist art in the event that it backfires on them?
On a not entirely unrelated note, as an adult, I was rather surprised to learn how much of the literature I was forced to read as a teenager [in government schools] had been written by out-and-out marxists: Upton Sinclair, John Steinbeck, Ernest Hemingway...
Heck, even most of the prominent children's authors of the twentieth century were, if not marxists, at least proto-marxists: Beatrix Potter, H. G. Wells, Ursula K LeGuin, Theodore "Dr. Ted" Seuss, Bill Peet...
And if you go into a Borders or a Barnes-N-Noble [or even a public library - but look out for the sodomites waiting for you in the bathroom], searching for a book to give a child, you'll find that 100% of all children's literature written in the last 30-40 years is pure, unadulterated, politically-correct, marxist-fascist claptrap.