[krapp]

>And they don't seem to have had any special trick to it, they just repeat the lie enough times that people believe it.

That is the special trick. It's a technique often attributed to Nazi propaganda minister Joseph Goebbels.

You don't need to convince people to believe a lie, despite arguments about "truth being the best disinfectant" and "good speech being the solution to bad speech," because belief is not a process of logical deduction, rather it's an adaptation to stimulus. Surround a person in an environment of coherent lies long enough and their minds will simply adapt to it.