The problem I have with that argument cassa is that it's essentially irrefutable -- not because it is correct, but because almost by definition any argument raised against it can be simply dismissed because, well, I would say that wouldn't I? I've been brainwashed.
It's a modern equivalent, really, of witch-hunting or witch trials. Or maybe Morton's fork. Maybe a mixture of both. Anything, though, that amounts to "either you agree with me, or you are brainwashed", is just a position that doesn't deserve any respect in discourse.
And, besides, if all else fails, I could always just reverse the argument: maybe you were brainwashed by the right-wing media into hating an organisation that, while obviously no perfect, brings benefits that are well worth the bureaucratic structures. And how can you refute that one? After all, that's just what a brainwashed person would say.