In general, erotic exhibitionist stories are not ethical. Exhibitionism involves inappropriate exposure of oneself in a sexual way, and promoting or sharing such stories can violate social norms and respect for others' privacy and dignity.
Yes, there is harm. Such stories often involve inappropriate and unethical behavior. They can promote objectification of others and violate social and moral norms.
One possible impact is that it can affect a person's values regarding sex and relationships. It may introduce ideas that are not in line with healthy sexual ethics. Additionally, it can cause discomfort or even trauma for some individuals, especially those who have experienced any form of sexual harassment or abuse in the past. Also, constantly engaging with such stories can lead to a preoccupation with sexual thoughts that may interfere with other aspects of a person's life, like work, study, or social interactions.
Most classic literature does not typically contain such explicitly erotic stories. Classic literature usually focuses on more general themes like love, society, and morality in a more refined and less sexual way. However, some works from certain periods might have allusions to exhibitionistic behavior in a more veiled manner, but not in the form of 'erotic stories' as we understand them today.