I definitely disagree with that statement! How can someone expect someone who barely graduated from HS to survive on their own??
Young adults that age lack maturity, work & life experience.
Now, should young adults prepare for adulthood by attaining a post HS education? Absolutely!
But, there is nothing wrong with a young adult staying at home while they attain a college or trade school education.
I do believe that parents should definitely prepare their young adult children to become independent. So, by the time they hit mid to late 20s, they will be off the titty and will be able to survive on their own.