This sentence was correct to a certain extent. In novels, villains were often depicted as people with no moral bottom line or even hooligans. However, some villains might become more cultured and more terrifying. For example, they might learn how to use power and skill to deceive others, or they might master some kind of magic or skill to make themselves more powerful. Therefore, this sentence means that even if a hooligan is cultured, as long as he remains a hooligan, he may still be dangerous. In contrast, if a person was cultured and could control his own desires and behavior, he might become a safer and more reliable character.