The reality is, anyone can be forced to believe anything.
Beat them enough times, threaten them enough times, displace their family enough times, starve them and/or make them unemployed enough times...
And they'll believe. Or die in the refusal. Meanwhile...if they're dead...who cares about them anymore? FOF--or the Soviets, or the Nazis, or the USG--can always rewrite history to make "those people" the bad guys.