It always become more blatant as the contradictions of capitalism intensify and the status quo becomes untenable. You see the same in Western European propaganda from the 30s, particularly in the Weimar Republic.
There’s this saying that sunshine is the best disinfectant, but that somehow feels less true right now. It seems like you can be openly crooked in a democracy as long as you appeal to a sufficient majority for other reasons not related to your crookedness.
Sunshine is clearly not the best disinfectant, since we see fascist rhetoric and violence spreading. Repeating a lie enough can work, especially when people are already angry and desperate. And especially when it's merely an intensification of the same rhetoric that capitalism spreads anyway.
Put differently, after capitalism has shifted the Overton window to the right by enough, fascism becomes more generally acceptable.