Helen Lewis, deputy editor, the New Statesman

There is no way that Oxfam has breached the rules on political campaigning with its latest advert, which says that "austerity Britain" has created a "perfect storm" that is pushing people into poverty. It is true that charities aren't allowed to devote themselves purely to political campaigns – that would make them lobbyists – or support a political party. But they are absolutely allowed to oppose a particular policy.

So what's really behind the complaints about the advert raised by Conor Burns, Charlie Elphicke and other Tory MPs? Clearly, some people on the right want to create a climate in which charities fear criticising the government; in December, Iain Duncan Smith made similar complaints about the Trussell Trust's statements on the rise in food bank referrals. Politicians would much rather charities restrict themselves to bemoaning poverty overseas, where it can't possibly be their fault, or indulge in generalised waffle about Bad Things Happening, without ever asking who or what might be responsible.

I'm the chair of Nia, a charity concerned with violence against women, and I see the same thing happening in that sector: ask people if they oppose rape, and heads nod so furiously there's a risk of starting a cyclone. But mention the awkward fact that it's mostly men doing the raping, and mostly women and children getting raped, and suddenly everyone is very embarrassed and wonders why you have to bring bloody feminism into it. It's not the job of charities to make us feel smug about that 50p we've dropped in the collection tin. It's the job of charities to make us feel ashamed and angry enough about ourselves to change the world.

Ruth Dudley Edwards, crime writer, historian and journalist

I don't think a charity is doing its job when it becomes so politically partisan that it drives away supporters. Among the charities I've stopped giving money to over the years are Amnesty and the RSPCA. Recently, Amnesty disgraced itself by snuggling up to pro-jihadists, while the RSPCA preferred to spend its money pursuing foxhunting rather than cruel factory farming. I've been dubious about Oxfam's tone for a long time: after seeing this poster, I've added it to my banned list.

Charities are certainly entitled to criticise policies that most reasonable people would think wrong, but they're not entitled to use their money for posters that could have been the opening shot of a Labour party political broadcast. Considering the financial crisis that hit this country some years ago, the UK is doing pretty well. Zero-hours contracts suit quite a lot of workers, inflation is low, benefit cuts have been introduced for the purpose of containing out-of-control spending and making it more attractive to work than not, unemployment is dropping fast, and the government is trying to do something about childcare costs.

The poster didn't mention food banks, but they feature on Oxfam's website with the half-witted argument that their rising numbers indicate rising poverty. In fact, they indicate rising generosity. As Robin Aitken, who runs the Oxford food bank, has pointed out: "If you provide a service, people will use it." I find it extraordinary that, at a time when tens of millions of desperate refugees are in need of our help, Oxfam chooses to waste its money on left-wing propaganda.

HL: Is Oxfam really failing if it drives you away? No. It's failing if it drives away a significant proportion of its existing supporters without attracting any new ones. That's an important difference. Giving money to any charity is an inherently political act – you say, for example, that you jettisoned the RSPCA when their focus switched to foxhunting. But they would never have been my first choice for a donation: I'd always rather give money to humans than animals. Similarly, I prefer secular charities to religious ones; the latter certainly indulge in a bit of propaganda alongside their good work (for instance, Catholic charities that oppose contraception, despite its proven effectiveness in combating poverty).

The charge that Oxfam is scaremongering is a more serious one. But I don't see the advert as party political: rising inequality and zero-hours contracts were a problem well before 2010, and any future Labour government would have to follow many austerity policies, almost certainly including benefit cuts. It's quite telling that some Conservatives feel attacked by this advert; it suggests they worry about being the nasty party more than they let on.

RDE: We'll see if Oxfam picks up more supporters with this campaign. My guess is that it'll lose, as the RSPCA did, to the detriment of those it's supposed to help. I don't see how it is political to give money to animals. I hate cruelty to any being that feels it, and rejected the RSPCA because it espoused toff-bashing rather than animal-defending.

Well-paid Oxfam staff seem more interested in expressing their right-on lefty opinions than in alleviating poverty. Hence their falling out with Scarlett Johansson because of her support for the SodaStream Israeli company that employed hundreds of Palestinians on higher salaries than those paid by Palestinian employers. I may be right of centre, but that's because I want the world to be better in practice rather than theory. My benchmark is effectiveness rather than high-sounding rhetoric, so although I'm an atheist I have a standing order to the Salvation Army because they're really good at dealing with the short-term problems that often plague people in trouble. And – unlike Oxfam – they don't try to indoctrinate me.

HL: I'm intrigued by that "well-paid staff" jab. Oxfam's chief executive is paid £119,560 – nearly five times the median British salary, for sure, but a comparatively low amount for someone responsible for 5,000 staff, thousands more volunteers and a budget of more than £360m. I dislike the idea that, unless you personally live in a shoebox and eat gruel, you can't campaign against poverty. We need charity bosses to be good at their jobs: if your benchmark is effectiveness, you'll be pleased that Oxfam has relatively low overheads for a charity of its size (just 9p in the pound). I think the grumpy Tory MPs complaining about the advert would have been better off echoing the prime minister's spokesman. His statement made clear he believes that austerity – or, as he called it, the deficit reduction plan – was necessary to restore economic growth. He didn't try to deny that and, as with any policy, there have been losers as well as winners. Charities must be free not just to identify an injustice, but also to talk about its causes. That might make us uncomfortable, but the alternatives – bland hand-wringing and shallow solutions – are far worse.

RDE: I wouldn't expect the head of Oxfam to subsist on gruel, but I'd like charity workers to see their jobs as vocations rather than a well-paid career providing both generous financial rewards and the opportunity to pontificate from the moral high ground. Their foot soldiers work for nothing. I'm glad you accept that any policy has losers as well as winners.

Why can't Oxfam accept that reality? And as Iraqis join the millions of desperate refugees, why is Oxfam training its guns on a well-meaning democratic government rather than persuading us to help the most wretched of the Earth?