“”...all illiberal left-wing ideologies, Marxist and otherwise, follow the same basic structure. These critiques reject the liberal notion of free speech as a positive good enjoyed by all citizens. They categorize political ideas as being made on behalf of either the oppressor class or the oppressed class... From that premise, they proceed to their conclusion that political advocacy on behalf of the oppressed enhances freedom, and political advocacy on behalf of the oppressor diminishes it.
The illiberal left is a talking point used by some liberals but mostly conservatives that claims some quarters on the left have somehow lost their way in regards to promoting the values of liberalism, especially in regards to free speech.
Like militant atheist or radical feminist, "illiberal left" can accurately describe a real movement, but in practice is a snarl word. There have indeed been illiberal left-wing movements: Mao Zedong himself wrote a pamphlet called Combat Liberalism in 1937, in which he argued that pluralism and civil liberties were mere bourgeois niceties. The term's misuse begins when one starts equating Mao — a tyrant who held power of life and death over one billion people--to a vocal transgender activist on Tumblr.
Jonathan Haidt characterises the illiberal left as being fundamentalist and authoritarian in nature and compares the intensity of their beliefs to that of fervent followers of a religion. He has spoken of his experience in university of "microagressions", "trigger warnings" and "safe spaces" and how they are actively encouraging the cognitive distortions that cognitive behavioural therapy seeks to correct, such as emotional reasoning, fortune-telling and magnification. He also states his alarm at the chill being placed on freedom of speech within the humanities and social sciences. He notes however that, thankfully, the natural sciences remain unaffected.