You'd be hard pressed to have used the internet in the past couple of weeks without coming across something Duggar-related. The stars of TLC show 19 Kids and Counting have been at the centre of controversy ever since it was revealed that eldest son Josh molested five underage girls, four of them his sisters, as a teenager.

Devout Christians, the Duggars have long divided opinion. Even before Josh's actions came to light, many criticised the family's conservative beliefs. They conform to a model of rigid male hierarchy and patriarchal gender roles, and have been accused of homophobia. Michelle Duggar earlier this year warned against allowing transgendered people to use the public bathrooms of their chosen gender, and the family are staunch proponents of the pro-life movement.

They are also often associated with the fundamentalist Christian Quiverfull movement, and though the Duggars deny that they are part of it, they follow many of the same principles. When the allegations against Josh were made, therefore, the family were accused of hypocrisy; how could they profess "strong family values" all the while knowing that their son had abused his sisters, one of whom was reportedly just five years old at the time?

Many Christians have come out in support of the Duggar family. Republican presidential candidate Mike Huckabee joined the defence, saying Josh's actions were inexcusable, but not unforgivable – though he has since removed all endorsements from the Duggars from his campaign website. Others have pointed to the family's honesty; that they sought outside help when they discovered Josh's behaviour, have consistently stressed that his actions were wrong and they dealt with the situation as best they could.

Except, their best doesn't seem to have been good enough.

In their first interview since news of the scandal broke, Michelle and Jim Bob Duggar told Fox News' Megyn Kelly that Josh was "just curious about girls". They appeared to suggest that his molestation wasn't as bad as it might have been simply because his victims weren't aware of what he was doing; either they were asleep, or too young to understand. "This was not rape or anything like that," Jim Bob said. "None of the victims really knew about this or understood what he had done until we went and told them."

"It was more of his heart, his intent, he knew that it was wrong," Michelle added. "But in theirs...to them [the victims] they probably didn't even understand that it was an improper touch."

This is at best incredibly naïve, and at worst an outrageous attempt to shield Josh at the expense of those he harmed. To imply that a crime – and molesting underage girls is a crime – can be valued based on how aware the victims are of the wrongdoing is absurd, and the whole Duggar family seems to be in on it. Even Jessa, Josh's sister and one of those he molested, has protested his vilification – "I do want to speak up in his defence against people who are calling him a child molester or a paedophile or a rapist, some people are saying. I'm like that is so overboard and a lie," she told Kelly.

"He was very sly, the girls didn't catch on," Jessa added. She was aged around nine at the time of the abuse. "It was very subtle, and so I think that for us, we realized this is serious, but at the same time, it wasn't like a horror story."

The Duggars' response to the scandal raises serious questions about the model of Christianity that they follow, and how healthy the environment is that it creates. The intense focus on family and the limiting of outside experiences – despite being the stars of a national TV show, the family does not have a television and all the children have been home-schooled – means it's not too difficult to see how a closed environment might be fostered. Not to mention the perpetuation of male hierarchy; it was hard to watch the Fox interview without flinching every time Michelle looked to Jim Bob for confirmation that what she was saying was okay.

That's not to say that following a conservative form of Christianity automatically leads to abuse, but we have to call to account any way of life that puts vulnerable people – especially children – at risk.