They're controversial because they often deal with themes that go against moral and ethical norms. Society has certain standards about appropriate sexual behavior, and these stories cross those lines.
Some common themes in taboo erotic stories might include non - consensual or forced relationships, which are extremely unethical in real life but are sometimes explored in a fictional and disturbing way in these types of stories. There could also be themes around fetishizing things that are considered abnormal or inappropriate in mainstream society, like having a fetish for certain body parts or substances in a sexual context.
No. Such stories are not acceptable in mainstream literature as they often contain explicit and inappropriate content that goes against moral and ethical norms.
Free erotic taboo sex stories can cause several problems in society. Firstly, they can influence the way people perceive sex, making it seem more like a casual and improper thing rather than an important and private part of a relationship. Secondly, it can contribute to the objectification of people, especially women. And finally, it can undermine the values that society has worked hard to build up, such as respect, modesty, and healthy sexual attitudes.
One negative impact is that it can distort people's views on healthy relationships. Taboo themes in such stories might promote abnormal or unethical behaviors in a relationship context.