From The Tyranny of Liberalism by James Kalb (2008: pp. 51-2):
Crude political expressions of scientism, such as Marxism, once waged open war on the traditions and religion of the people. Contemporary liberalism, which supplements scientism with the claim of tolerance and popular consent, is more sophisticated.
It accepts the right of tradition and religion to exist, but it trivializes them as mere personal preferences that cannot be allowed to affect anything that matters.
Furthermore, the disciplines of mental health remain available to delegitimize popular preferences at odds with public policy.
These disciplines were used as political tools with Bolshevik crudity in the Soviet Union, but they have been deployed with greater finesse in the West.
Classic examples include Theodore Adorno's critique of the 'authoritarian personality', which allowed almost any sort of skepticism regarding liberal demand sot be treated as a sign of psychological disorder, and Richard Hofstadter's 'The paranoid style in American politics', which assimilated support of Barry Goldwater and dissent from the Cold War-liberal consensus to a pattern of political insanity that spanned centuries.
A more recent example is the term 'homophobia, which turns adherence to traditional sexual morality into a mental disorder.'
What has happened is that liberalism/ political correctness has become so pervasive an assumption among the intellectual elite, that they regard PC as not just statistically normal, but as natural and spontaneous such that any deviations require specific explanation.
A related example of this, written by a friend of mine and indeed the premier IQ researcher in the UK, shows the Leftist assumption that intelligent people will naturally gravitate towards 'liberal and antitraditional social attitudes' and the strong implication that such attitudes are 'enlightened' in the sense of Good:
Bright Children Become Enlightened Adults. Ian J. Deary, G. David Batty, Catharine R. Gale. Psychological Science January 1, 2008 vol. 19 no. 1 1-6. Abstract: We examined the prospective association between general intelligence (g) at age 10 and liberal and antitraditional social attitudes at age 30 in a large (N = 7,070), representative sample of the British population born in 1970. Statistical analyses identified a general latent trait underlying attitudes that are antiracist, proworking women, socially liberal, and trusting in the democratic political system. There was a strong association between higher g at age 10 and more liberal and antitraditional attitudes at age 30; this association was mediated partly via educational qualifications, but not at all via occupational social class. Very similar results were obtained for men and women. People in less professional occupations—and whose parents had been in less professional occupations—were less trusting of the democratic political system. This study confirms social attitudes as a major, novel field of adult human activity that is related to childhood intelligence differences.
I agree with Deary et al that higher IQ does indeed predispose towards PC and 'enlightened' attitudes - but I regard the word 'enlightened' as meaning something-like 'progressivism typical of the enlightenment era' rather than being conflated with 'virtuous'.
So I regard high IQ enlightenment as a 'clever silly' phenomenon - a phenomenon among the current intellectual elite which is a by-product high IQ among European populations.
High IQ has definite advantages in terms of social success and longevity in modern societies.
But it is the historically- and geographically-restricted attitude of liberalism and anti-traditional values which is objectively, biologically pathological - as revealed by the cumulatively-lethal effect on reproductive success among the intellectual elite and the societies they rule.
The scientifically-correct response to accusations of mental illness among anti-PC traditionalists is therefore not to argue-against the whole idea of psychopathology as relevant in politics; but in fact to make the credible counter-argument that significant (because fitness-damaging) psychological disorder is endemic among progressives.