This discounts the effects of things like shills (commercial or government) or propaganda in general and its quieting effect on discussion. Yes, there are conspiracy theories, but there is a reason why they end up relegated to the quacks and aren't broached upon at all, save for in jest perhaps, by mainstream sources of information. I mean really consider the actual diversity of thought among mainstream sources in this country. It is astoundingly limited and entirely biased towards neoliberalism. Our political spectrum is extremely narrow and differentiated by only a small handful of hobby horse issues.