It could also be a matter of Hermione's self - sacrifice. She is a very selfless character in general. If she sees Snape in immediate danger and realizes that his death would have far - reaching negative consequences, she might step in without a second thought. For example, if Snape holds the key to some important magical knowledge or power that is needed to save the wizarding world, Hermione might sacrifice herself to ensure he lives to use it.
Maybe in that fanfiction, Hermione has come to understand Snape's past and his connection to her friends in a way that makes her believe his life is crucial for the future. She could have discovered some deep - seated secret about Snape that convinces her that his survival is necessary for the defeat of Voldemort or for some other greater cause.
One possible motive could be Hermione's sense of justice. She might see Snape as a misunderstood figure who has been doing things for the greater good all along, even if it doesn't seem that way on the surface. So, she decides to sacrifice herself to save him.
One possible reason could be that Snape sees Hermione's value as a brilliant student. He might recognize her potential and not want it to be wasted just because of her dad's actions or situation. Maybe he has a sense of justice deep down, despite his often cold exterior.
One reason could be Snape's sense of justice. Despite his often - cold exterior, he might not tolerate Draco's bullying behavior towards Hermione.
One possible motive could be Snape's complex relationship with Harry's father. Snape might see Harry as a way to get back at James in some twisted way. He could also be acting out of a sense of duty to the Dark Lord, believing that taking Harry by force is part of some larger plan to gain power or favor.
Well, one reason could be that he sees her intelligence and thirst for knowledge, which he respects. He might feel a sort of kinship as he was also a very intelligent student himself when he was younger.
Another motive could be related to her family. Maybe there was some sort of blood feud or an old grudge against the Grangers. The kidnappers could have thought that by taking Hermione, they could get revenge on her family. In some fanfictions, there are secret magical families that have long - standing rivalries, and Hermione's kidnapping could be part of that.
One possible motive could be power. In some fanfictions, there might be dark wizards or witches who believe that Hermione, being a very intelligent and magically gifted child even from a young age, could be used to their advantage. They might think that they can control her magic or use her knowledge for their evil plans, like finding ancient magical artifacts or unlocking powerful spells that are otherwise inaccessible.
In these fanfictions, a common motive for Hermione's kidnapping could be her unique knowledge. She is known for her extensive reading and understanding of magic. Some villains might want to use that knowledge for their own gain. For example, they could be looking to uncover ancient and powerful magic that Hermione has studied. Regarding the adoption part, it might be a way for those who kidnap her to control her future. They could think that by 'adopting' her, they can shape her into someone who serves their interests better. It could also be related to a prophecy. If there is a prophecy that involves Hermione in some way, certain groups might kidnap her to either prevent the prophecy from coming true or to make it come true in a way that benefits them.
One reason could be Snape's sense of justice. Despite his often - cold exterior, he may not tolerate Ron's unjust behavior towards Hermione. Another reason might be that he sees something in Hermione that he values, like her intelligence or her thirst for knowledge, and doesn't want it to be extinguished by Ron's actions.
Some writers might do it for shock value. They know that the relationship between Snape and Lily is so beloved and complex in the original story that by creating a very different and extreme scenario like harassment, they can draw more attention to their fanfic.
It could be a failed experiment in potions class. Hermione is always eager to try new things in potions, and perhaps this time it backfired, causing her some harm. And Snape would be the one to find her because it's his class.