When one discusses socialism with socialists, one will hear that a socialist country never actually existed. Sure, there were attempts at establishing socialist nations, but since they failed miserably, they don't count.
Since a socialist nation has never truly existed, despite the many attempts, is there a point to supporting such a system? Sure, ideally, it'll work perfectly, but everything works perfectly on paper. How is socialism, which won't ever work unless the most ideal variables are in place, different from the belief of magical fairies from Neverland maintaining the world's peace and economy? Some will still insist though that socialism is better than system we have now, because although it doesn't work nearly as well, it's "nicer."
Since socialism doesn't work well except in small doses as America has it, why even bother supporting some make-believe utopia that'll never be? It might be nicer, but niceness doesn't do as much for the world as practicality.