The Scottish Greens are not happy with the prospect of Kate Forbes, a believing Christian and member of the Free Church of Scotland, being elected First Minister. In fact, they are so unhappy that they have suggested they would withdraw from their partnership with the SNP to form the Scottish government if she wins.

The issues that seem to rile them the most are not 'Green' issues such as the environment and saving the planet, but progressive social issues such as conversion therapy. Until last week their leader, Patrick Harvie, had publicly stayed out of the fray, but after the Sky leadership debate he weighed in and the Greens suggested that this is a deal-breaking issue.

Why has conversion therapy become a major issue? Why has it overtaken euthanasia as a cause célèbre for 'progressives' throughout the Western world? Has there been an epidemic of conversion therapy? What is this great evil that needs to be banned and is seen as so important?

I agree it is a major issue, which is why I have written about it for Christian Today before - here and here. But it is not a major issue because it is a widespread problem in our society. Instead, it is a major issue because it is a Trojan horse being used to smuggle in an anti-Christian, authoritarian ideology.

Let's return to the exchange between the Scottish Greens and Kate Forbes. In the debate, Forbes stated: "I think people should be allowed to live freely as they choose, and I don't think there should be conversion therapy in existence in Scotland."

In response to a question about whether a gay man should be allowed to seek conversion therapy to change his sexuality, Forbes said: "Well, it's his choice, but I do not think we should allow conversion therapy."

It was this latter comment that caused Harvie to explode: "Anti-LGBTQ+ conversion practices are abhorrent and abusive by nature. There is no such thing as a non-coercive conversion practice and never can be. Anyone who argues that people should be able to consent to this form of abuse is clearly failing to understand the issue."

Christian cultural commentators often observe that 'consent' is the shibboleth of our culture. It is. But only if you consent to the 'right' things. You can consent to abortion, euthanasia, sex, drugs, pornography and gender transition, but you cannot consent to seeking help for unwanted sexual attraction. This is neither logical nor consistent, but then logic and consistency are not that important for the progressive ideologues. For Harvie and colleagues it is even the appearance of being anti-LGBTQ which means that it should be banned.

Some Christians have asked: why did Kate Forbes say that conversion therapy should not be allowed in Scotland? Because it all depends on what you mean by conversion therapy – and this is where the heart of the issue really lies. When people hear the words 'conversion therapy' they automatically picture abusive practices such as electrodes, violence, rape and brainwashing – which I would hope all of us would oppose (and which are already illegal). But that is not what the progressives mean when they are talking about conversion therapy. They use words like 'torture' to refer to a much broader spectrum.

The Scottish Parliament set up an 'Expert Advisory group on Ending Conversion Practices' and these 'experts' came up with an extraordinary definition: "The definition should be consistent across sexual orientation and gender identity and must be wide enough to encompass all acts and practices that seek to change, suppress, or inhibit someone's sexual orientation, expression of sexual orientation, gender identity or gender expression."

This is no longer just about seeking to 'change' someone's sexuality etc, but also who seek to 'inhibit' and 'suppress'. It's an extraordinarily authoritarian measure. For example, if a pastor urged someone who was experiencing unwanted sexual temptations (whether homosexual or heterosexual) to live a celibate life, he would be breaking the law. If a teenage girl wanted to live a promiscuous life and go to all night sex parties, her parents would be breaking the law if they sought to stop her or discourage her. If you suggested to wee Johnny that his desire to be wee Jenny would pass, you would be breaking the law!

Harvie said during the debate that, "Nobody should be told that they are not good enough or that they should be ashamed of who they are." Which sounds cute enough as a meaningless meme, but is clearly nonsense. Mr Harvie does not think that the Tories are good enough and should not be ashamed of who they are. I presume he thinks that racists, paedophiles and climate change deniers are not good enough and should be ashamed of who they are! He is referring to one particular group and ideology – his own, which he wants to have special protection and privileges.

Although the progressives have a broader spectrum for the definition of conversion therapy, they have a much narrower definition of who it should apply to. For example, when the UK government decided to include seeking to convert someone to transgenderism in their proposed ban, they exploded with rage.

The then government minister Liz Truss had said: "The proposed protections are universal: an attempt to change a person from being attracted to the same-sex to being attracted to the opposite-sex, or from not being transgender to being transgender, will be treated in the same way as the reverse scenario. They therefore protect everyone."

This was considered abhorrent. The progressives think that a teenage girl has the right to have a double mastectomy and a seven-year-old has the right to puberty blockers to aid them in their gender conversion. But someone praying with a person who has unwanted sexual desires is evil and should be jailed!

The proposed conversion therapy laws are nothing to do with preventing abhorrent and abusive practices. They are everything to do with imposing an ideology upon the whole population. In particular they seek to change, suppress and inhibit Christians from practising and teaching Christ. If nobody should be told they are not good enough and that they should not feel ashamed of who they are, then we are banned from preaching the Gospel. For it is Jesus who tells us that none of us are good enough and that all of us should repent.

The Good News is not that we are all great and should feel no shame. The good news is that we are far worse than we think we are, and far more loved than we could imagine. The Gospel is about conversion to a new life, new hope and new future. No parliament will ever be able to stop us preaching that.

David Robertson leads The ASK Project in Sydney, Australia. He blogs at The Wee Flea.