I think that liberals have been fragmented by conspiracy theories for a very long time, but I don't see the anti-science part. /me
I think maybe the reason behind the dumbing down theory is a basic problem of intellectual dependence in our society, with public schools and television being to blame.
Take a look at almost any primary or secondary classroom, and you see when a kid doesn't understand something, they raise their hand. No, they don't look through their books or look at what notes if there are any, they are dependent on someone else to 'learn them'.
How many times have we heard, "Just tell me what to do!" in moments of great frustration? We're so conditioned to receive 'teaching' against our desire, that after 12 years of schooling, free will and curiosity are almost completely destroyed.
If you look throughout the world, generally you'll see a negative correlation between amount of schooling per year and performance.
John Gatto has written a book about the history of American compulsory schooling, his thesis being in that modern schooling was invented in India to reinforce the caste system (further refined by Prussia), schooling was forced onto America by the Utopian intelligentsia and elite business interests like Carnegie, Ford, Rockefeller, to dumb down and crush the independence of Americans.
'Tis an interesting read.
Dependent people won't disturb the economic order, and bored, incomplete people will require excessive managment and will buy more stuff.
Does it really take 20+ years to 'grow up'?
edit: the supression by liberals reminds me of that guy in france that wrote a book about how the holocaust didn't really happen. I think he lost his job or something, but Noam Chomsky came under attack for supporting this guys right to say what he wanted. Silly Frenchies!