For example, are you critical of the floor being solid when you get out of bed? You probably wouldn't spend extra milliseconds contemplating they hardness of the floor. Now let's say you get up and the floor is wet. You might take a moment thinking about what happened, looking up at the ceiling, whether the dog peed, did someone spill water, etc.
That is an extreme example, but many people find it very difficult to critically analyze everything they come in contact with. It helps immensely that things like political opinions are controversial, so we are at least aware of other possibilities, but it is still very difficult to accept something that contradicts what is established in our minds, even when that which is established is wrong. So it isn't just that we need to be critical, it is we must be somewhat critical[0] of even things we believe when there is at least some doubt to their validity.
[0] I actually wouldn't call this being critical, but rather, being open-minded to being incorrect.
Plenty of dumb people everywhere. Fake news, state news, no news, they'll eat it up.
I've basically given up on trying to show anyone any sort of truth. A third of my life is over and we're not even to the point where 10/10 people could tell you which way is up without consulting some blog or CNN.
I just gotta carve the best life I can, regardless of any mob rule.
Not to mention doing a sweeping generalisation on 300+ million people.