Anyone who’s gotten an email from a Nigerian prince has wondered why they’re so poorly written. The reason is that they’re sorting out the gullible. The type of person who would respond to such a bad email is more likely to be the type of person to actually send money. And once they engage, they’re less likely to question themselves because they’ve already committed to the idea that the email is real.
This is an example of a shibboleth and confirmation bias. A shibboleth is a word that only a specific group would say. Ok, it’s not exactly a shibboleth but it’s similar and I think more people should understand the concept. Point is, the email selects for people who are the target audience. Confirmation bias is when you only see the confirming evidence, neglecting dissenting evidence, because you’re disinclined to change your mind.
Politicians blatantly lie and do stupid things. Most people see the opposing politician and think that their supporters must be idiots while missing that their politician is doing the exact same thing. I think they’re acting like Nigerian princes. By saying stupid things, they’re selecting for a group that will become their base. And once they’ve committed to agreeing to something stupid, it’s hard to walk away.