There is nothing new about what some have termed the new intolerance. It’s just that contemporary intolerance is more intense and all-embracing than once was the case.

Writing in The Spectator this month, Rod Liddle reflected on the gay marriage the BBC recently featured on Songs of Praise, which broadcasts hymns from churches. Not surprisingly, the program led to numerous complaints from conservatives — all of which were dismissed out of hand.

Liddle commented: “You might think that the BBC would allow a tiny corner of its output to be free of the progressive agenda which it shoehorns into every other program. But nah, not a bit of it. Every single area of output must toe the line: there is no alternative.”

Since Federation in 1901, Australians have more often than not supported right-of-centre governments. However, the left is particularly strong in government-funded institutions, especially in the social sciences and the media. A leftist mindset pervades the ABC and dominates in the social science departments of the universities. This has been a fact of life for at least the past half-century. It’s just getting worse.

I recall being marked down in an essay I did in the Asian studies department at the University of Melbourne in the late 1960s. My sin was to write that agricultural production in China in the 50s and 60s, under the Mao Zedong communist dictatorship, was lower than when nationalist Chiang Kai-shek ruled China before the October 1949 revolution.

I was told by a leftist pro-communist academic, who relied on official Chinese statistics, that this was an error. When figures were eventually released — following Mao’s death in 1976 and the end of the Cultural Revolution — they indicated that I had actually ­underestimated the crisis. After all, we now know that 45 million died in Mao’s Leap Forward between 1958 and 1962 due to the forced famine.

I am aware of a student who suffered a similar fate at the University of Sydney in the late 90s. The sin? Well, one leftist marker of a thesis objected to the statement that many Australian academics uncritically supported Mao’s totalitarian regime throughout the Leap Forward and the Cultural Revolution between 1958 and 1976. But this was the case — even if many leftists went into ­denial about repression in China until after the Tiananmen Square massacre of 30 years ago.

From the mid-60s, the left on campus had attempted to shut down debate by exercising censorship over the student press and attempting to prevent individuals with whom they disagreed from speaking on campus. All that has happened in recent years is that the left has attempted to eliminate dissent in more and more areas.

What used to be regarded as mob rule now has the seemingly respectable title of de-platforming. And whereas the left was willing to let a few ideologically unfashionable views exist, now there is a tendency to silence all debate by refusing to hear alternative views. There is a more vibrant debate outside the academy on a range of issues, including climate change.

The most recent version of what was once termed the authoritarian personality can be found in the decision by taxpayer-funded online publication The Conversation concerning the climate debate. On Tuesday, Misha Ketchell, its editor and executive director, advised that from now on he would adopt “a zero-tolerance approach to moderating climate change deniers and sceptics”.

Now it’s true that a large number of climate scientists, many of whom work in universities and government agencies, share Ketchell’s view that failure to act on climate change immediately “will ultimately destroy the planet”. But not all. Yet everyone, including the occasional climate scientist, who does not share Ketchell’s eco-catastrophism will be de-platformed with respect to The Conversation.

Editors cannot be expected to publish all contributors. And there are the trolls who, irrespective of what side of the debate they are on, do not fit in a publication such as The Conversation. But Ketchell has decided to cease being an editor making decisions concerning research, writing style and the like. Instead he has embraced the role of censor. This does not make sense, even from an eco-catastrophist perspective. For in this area it should be possible to enter a discussion about the extent of the urgency and timing of what needs to be done. And then there is the wisdom of knowing what those who disagree with you are saying and writing.

A clever conservative should be across the views and actions of the left, just as a smart leftist should know what conservatives are saying and doing. The problem with the modern left is that it has embraced what German-born Marxist Herbert Marcuse (1898-1979) termed “liberating tolerance”. By this he meant the need for “intolerance against movements from the right and toleration of movements from the left”.

Few these days would have heard of Marcuse. Yet in the half century since his 1965 book Repressive Tolerance was published, his views have found root in many areas of the education system and sections of the media.

The usage of the word conversation has become a tiresome cliche. That aside, it is a misnomer for Ketchell to call his taxpayer-funded publication The Conversation, since it preaches what he regards as the climate faith rather than engaging in debate and discussion. Perhaps it could be renamed, say, The Truth According to Ketchell.

Once Ketchell has banished anyone with a different opinion to himself on climate change from The Conversation, there will be more room for the likes of eco-catastrophist Tim Flannery. Last week, in an article first published in The Conversation and reprinted in the leftist Guardian Australia, Flannery called Energy Minister Angus Taylor an “idiot” and said the likes of Alan Jones and Andrew Bolt posed an “immediate threat to our children”. This is a university publication.

Australia’s tertiary institutions for many years have not been ­places of reflection and discussion. And, year after year, they become more hostile to debate as the left refuses to hear what it does not want to hear.