This reminds me of the Socrates quote: "The ancient oracle said that I was the wisest of all the Greeks. It is because I, of all the Greeks, know that I know nothing."

Critical thinking doesn't end when you believe you've found an answer to your question. Critical thinking depends upon you questioning that answer, disseminating it further to find more behind it. An example: 9/11 WAS AN INSIDE JOB! But who were the perpetrators? Was it the entire US government, or a small collective? Did they use outside help, and hire people to hijack planes, or were the hijackers claimed posthumous? What was the motivation behind the attacks? Was it merely a reason to begin a war in the Middle East, or was this a byproduct of the assault which was committed for far larger reasons? If hijackers, or Al-Qaeda were involved, were they aware they were being used by the US government? Yet so many seem satisfied with simply "9/11 was an inside job".

It is those people mentioned above, those satisfied with an answer that they don't look to question, who make up broad sectors of society as 'critical thinking' is slowly being drained through the education system and media outlets - alternative views to socially-accepted 'facts' are often scoffed at so people take 2 sides, accept the social, or accept the anti-social. When a person finds an answer they're satisfied with, they stick with it all guns blazing, ignoring contrary evidence if and when necessary (such as the early detractors of the heliocentric model of the galaxy). Hopefully, to make my point clearer, I have no evidence of this other than "science told me", and only realising now that I've never truly questioned this model; it seems to make sense, but without questioning it becomes no more than a cliche to fall back on. I can only hope that if I stumble upon evidence that points to the contrary, I don't turn my nose up and claim it heresy out of natural instinct. Ultimately, people don't like being wrong, they like being proven right and will focus on materials that further affirm their beliefs.

For me, I can't watch the BBC or Channel 4 News now without seeing propaganda plastered across the screen. I find myself questioning everything they say due to their linear, singular-perspective view, such as the situation in the Ukraine - very little mention of the Western coup installing a pro-EU Prime Minister, overthrowing the democratically elected pro-Russian Prime Minister, yet because the rebels are fighting the government, and the government is pro-EU, we are expected to side with NATO against the Russian rebels despite it being their country.

Meanwhile, I find myself hovering around C_S_T, conspiracy (though now dwindling for the reasons you stated), and focusing on material to the contrary of the publicly-accepted slant, such as Gods of Eden by William Bramley. I claim it to be so that I can get a better view of the opposing, yet I seem to be on the opposing side, and find a guard rise when the Mainstream comes up with another linear view. Perhaps critical thinking is, quite simply, a dying concept. As the world becomes divided between what's socially acceptable views, those who are looking for alternatives find themselves scoffed or scorned by society, so they look for like minded people to assure them that they aren't crazy, that what they've read/witnessed/experienced is a true and valid concept, and perfectly acceptable to entertain as a thought, or even as a truth.

Critical thinking is being maimed by repression of thought, and the more the public accept faltering stories such as the Warren Report of the official 9/11 story, the more the two groups will become divided. The shepard has taught the sheep to keep themselves in the pen, if you will, and thus critical thinking is frowned upon causing those who attempt to find alternatives to become frustrated - the worst possible emotion for someone looking for the truth.