It's not. If you are brainwashed, you have no conscious control over the way your brain thinks. I can assure you that everybody is socialized and indoctrinated to some extent. Even your belief that there is such a thing as people purposely chosing to stick to what they believe because they want to be ignorant is the result of socialisation in your particular culture.

People who grow up in Muslim countries believe in Allah. People who grow in up Christian countries believe in Jesus. People who grow up in Hindu countries believe in Shiva. People who grow up in secular countries believe it's bull. And people who grow up in the Marvel Universe believe that Thor and Spiderman and Ironman are worth talking about!

For someone to turn around and say that others are willfully ignorant because they don't want to switch ideologies is a show of remarkable arrogance.