I don't know why they give this racist has been or more accurately never was the time of day. Just ignore him and and leave him to his own little bigoted world.
What exactly did Brash say that was racist? Did he threaten to kill all the maoris, or that he hates maori?
Specifically: he objected to non-translated te reo for audiences who were almost entirely non-fluent in te reo. He referred to Guyon on RNZ but also to meeting attended by a non-Maori audience that commenced with a non-translated mihi. He also said he supports tax-payers funding of te reo platforms. I guess he could be accused of separatism -which is a form of racism.
He is an intelligent, intellectual man and I imagine speech from which he can't glean information irritates him. He also said he has no interest in learning te reo, but wishes he spoke mandarin - a statement which people may interpret as racist if they specifically want to.
I still think he is trying to limit the free speech of others, for something that is at worst an irritant or inconvenience to him and therefore he is wrong.
But he has the right to express his view too. He should have the common sense to know he is picking a fight he can't win. As a wealthy-white-male, he is the spawn of Satan in the eyes of a liberal audience before he opens his mouth.
Ultimately I think free speech prevails.
My grandmother taught me a little of 'the Gaelic' (she was fluent). If I wanted to prattle on in Gaelic in front of an audience who don't understand it I can (for about 30 seconds!). Free speech gives me that right. I don't because the audience wouldn't understand it and consequently I think it would be pointless and impolite.
It's also not exactly racist to object to a language in that context, I feel.
It would be (or at least could be) if he was objecting to it's use at all, ever, anywhere. However, objecting to the occasional and somewhat pointless (from a communication point of view) use of it on a National Radio station is not really racist, whether you agree with it or not. Of course, these days, just about anything is racist, fascist, sexist, or something-you-never-knew-about-ist so perhaps we ought not to be wholly surprised.