[Isamu]

You are right, I am being casual in asserting what “people prefer”.

You assert that people prefer to be right, I agree but in practice “being right” requires having to accept changes in your beliefs, and that’s painful.

Also “being right” requires some effort to check what the facts are, and that is arduous when people are busy with life.

As a result I think people prefer to feel like they’re right rather than dig deeper, and so they prefer information sources that tend to confirm their beliefs.

[munificent]

Behavior makes a lot more sense when you realize that humans are trying to have as accurate a view of the world as possible while also conserving cognitive resources. Running a brain is actually astonishingly expensive in terms of calories, so we've evolved to be judicious in how much thought we put into things.

Changing an existing belief is hard because we already spent effort acquiring the belief in the first place. Throwing that out should be expensive because otherwise we risk thrashing where we are constantly vacillating between competing beliefs. It makes more sense in terms of efficiency and being able to take action if there is some hysteresis and beliefs are sticky.

Note that while people don't change beliefs easily, they do acquire them pretty easily. If I tell you something that doesn't directly conflict with an existing belief, it's easy to absorb.