I'd say it's both! If the recipient is in an "us versus them" mindset, then they are going to be biased toward poking holes for ideas on the "other side". See

I'd say it's both! If the recipient is in an "us versus them" mindset, then they are going to be biased toward poking holes for ideas on the "other side". See also: "Why you think you're right -- even if you're wrong", by Julia Galef [video] https://youtu.be/w4RLfVxTGH4 https://youtu.be/w4RLfVxTGH4 There are obviously ways to present facts that cause people to be predisposed to rejecting them. I would argue that there are also techniques that can help pull people out of this mindset (for example, acknowledging that the listener's opposing view is a valid one), which can improve the odds of them being receptive to new information.