Answer:
this perspective is inaccurate because characters using informal language doesn’t mean that they’re unintelligent.
Step-by-step explanation:
it’s the same thing for formal language. there’s a time and place for both informal and formal language. if a bunch of characters are friends and hanging out, then they’d want to use informal language with each other. informal language can also be more realistic to use for characters. for example if all characters in a book are in high school, it would be really unrealistic to have all of them use formal language and walking around talking like they're in a job interview.
those critics are assuming that informal language = unintelligent characters when that is just not true. characters can be intelligent and still use informal language because that’s normal for them or they’re in a place with people where using informal language is better.