Sometimes the point of a lie is to make you STOP believing in anything, including the truth.
Spread so many lies, obvious lies, outrageous lies, easily disproved lies, until people lose all trust in the system itself and it doesn't matter if they ever hear the truth.
Only if you know the real numbers. A big part of the problem is how few people understand what normal actually is. Everyone I've asked to guess how many Americans die every year just under normal circumstances has guessed too small, some by as much as two orders of magnitude.