Everyone – or Twitter, at least – is calling it the most humiliating encounter ever. The Green party leader, Natalie Bennett, was interviewed by Nick Ferrari on LBC today, and her answers on housing policy were more ridiculed and scorned, more discredited even, than her exposition of basic citizen’s income on Andrew Neil’s Sunday Politics.

This encounter was worse because Ferrari is a more courteous interviewer than Neil, so Bennett didn’t even have the appeal of the underdog. As Ferrari told her, she should have “genned up” for questions as basic as “How much will each of your houses cost?”. Worst of all, she fell silent. At one point, Bennett said she had a cold – the interviewing equivalent of showing a predator your neck at the moment that they kill you. They might say something nice about Lemsip, but as far as they are concerned, you are dead.

And now Bennett will have to cope with people forever calling her “discredited”. It is the new mantra of the right, covering everything from an honest mistake to a statement they disagree with. They love it because it accrues authority to them (they bestow and withdraw “credit”) and because of its finality. Bennett, I would hope, knows that this is nonsense: that you’re discredited if you believe lizards are taking over the world, but you’re not discredited if you fail to recall how much is spent giving mortgage tax breaks to buy-to-let landlords.

If I were her, I wouldn’t worry about it: people who are anywhere near voting Green will recognise that a far more profound change to the distribution of government spending will have to be undertaken if we want to reach a housing settlement than will ever be teased out for the first time in a five-minute radio segment.

Nevertheless, there were mistakes in the Bennett interview. “We have lost faith in any of the large available understandings of how structural change takes place in history,” the philosopher Roberto Unger said in a recent lecture in London, “and as a result we fall back on a bastardised conception of political realism, namely that a proposal is realistic to the extent that it approaches what already exists.” This is the whole of British politics encapsulated in two lines: unless a policy looks exactly like what the mainstream parties are suggesting; unless it can be funded by minor tootling on existing tax instruments (and even that will be called a “raid”); unless it will leave the fundamental structures totally unperturbed – then it is the most outlandish idea that anybody has ever heard.

Therefore, nobody in opposition – not Bennett, not Ed Miliband, not Nigel Farage – should ever get into a conversation about how they will fund something without first underlining that the way things exist at the moment is completely wrecked. The status quo is broken; it’s not even static, it’s constantly worsening.

In the current spending round, £96bn was allocated to housing benefit, £5bn to building new homes. It is a naked redistribution of taxpayers’ money to the 2% of people who are landlords. Money we could be spending on decent, environmentally friendly housing stock that everybody would want to live in is instead being funnelled directly to the richest people in society: a system steadily creating dependence, insecurity and squalor, with 21% of people now on housing benefit. How many more have to join them before the boot is on the other foot and Nick Ferrari is called upon to explain what’s so great about the system as it stands? 30%? 50%?

Bennett came unstuck with the £60,000-per-unit costing, which Ferrari leapt upon. (What would that build, a conservatory? How much is the land costing? And so on.) In fact, I would venture that the Green party leader knows a lot more than Ferrari about building new homes: Green Cities is just one eco-think-and-do tank, which has produced blueprints for food neutral, energy neutral homes, costed at 10,000 flats for £1billion (100k each rather than 60, assuming that the land was bought by compulsory purchase order).

I would venture that the Green party leader knows a lot more than Ferrari about building new homes

Her mistake was to answer the question as Ferrari posed it, rather than describing the vision that she knows back to front; I can see why. We are all sick of hearing politicians simply address the question they arrived to answer. We claim to want to hear people listening, like human beings. But she needs to be able to frame the conversation around her own assumptions – that this housing would represent a radical, even beautiful new future – rather than his: that it would be a shanty town thrown up with plywood.

Least important, but most memorable, is the fact that Bennett freaked out. Like horses, these interviewers can smell fear; I wonder if they can even smell fear when she walks in. But the only way to deal with that is to get back in the saddle.

• This article was amended on 2 March 2015. An earlier version said that in the the final spending period of the Labour government, £96bn was allocated to housing benefit and £5bn to building new homes. Those figures are for the coalition government’s current spending round.