Probably misinformation. Some might misunderstand or misinterpret certain elements in the Harry Potter series and wrongly assume it has something to do with red dragon fanfiction, but in fact, there's no real connection.
It's most likely a completely wrong idea. There's no aspect of the Harry Potter story that would suggest it's a red dragon fanfiction. The story is firmly set in the wizarding world of Hogwarts, with a focus on Harry's journey, his friends, and his battles. There are no elements that are characteristic of red dragon fanfiction, such as a focus on the lore or behavior of red dragons. The magic in Harry Potter is more about spells, potions, and wands, not about red dragons.
I think it could be due to overactive imaginations or a lack of understanding of what Harry Potter actually is. Maybe some people see the magical creatures in Harry Potter and, in their confusion, think it could be related to red dragon fanfiction. However, the magical creatures in Harry Potter are very different from the focus on red dragons in fanfiction. For example, in Harry Potter, we have creatures like thestrals which are very different from red dragons in terms of their nature, role in the story, and the overall theme. Also, the main plot of Harry Potter is about the wizarding world's struggle against Voldemort, not about red dragons.
Some people might think this because of the common theme of a young hero on a journey. In both, there is a central character who has to face great challenges and grow throughout the story. Also, the use of magic or some form of special powers is present in both. In Pendragon, there are powers related to the different worlds and in Harry Potter, there are spells and magical abilities. This similarity in the basic structure of the story could lead to such a thought.
Some might think so because of the theme of a 'chosen one'. In the Noah story, Noah was chosen by God to save the animals and his family from the flood. Similarly, in Harry Potter, Harry was the chosen one to defeat Voldemort. But this is a very basic similarity and doesn't really make it a fanfiction.
People may think this due to the fact that both deal with a form of power that is not fully understood by the outside world. In Harry Potter, magic is a powerful force that only wizards and witches can truly master. In Atlantean lore, there was often some sort of super - advanced knowledge or power that was associated with the lost city. But really, these are just broad similarities and not enough to label Harry Potter as Atlantean fanfiction.
Some might think so because of the out - of - this - world and often zany elements in Harry Potter. Just like in a flounder fanfiction where the author might come up with really strange and unique ideas, in Harry Potter we have things like talking portraits, flying broomsticks, and magical spells. These elements are so different from the normal world that it could give the impression of being part of a more off - the - wall fanfiction.
Some people might think so because of the use of common fantasy tropes. For instance, the idea of a young hero in a magical world facing great challenges. These tropes are also present in some Warren fanfictions, so they may draw the comparison.
The popularity of Harry Potter and the fact that it has inspired so much derivative work could lead some to think it's a fanfiction. It has such a large and passionate fan base that has created countless stories, art, and interpretations based on it. This makes it seem as if it might be part of the fanfiction realm, when in fact it is the original work that inspired all these fan - made things.
One reason could be the way Harry Potter observes and gathers information. Rangers are good at observing their surroundings, and Harry is often in situations where he needs to do the same. In his search for Horcruxes, for example, he has to be very observant of the places he visits and the people he meets. This aspect of his character might remind some people of the skills that a Ranger would possess, thus leading them to think that Harry Potter has elements of a Ranger fanfiction.
Some people might think Harry Potter is apathetic in fanfiction because the writer wants to explore a different side of his personality. Maybe they want to show how he could be if he had different life experiences. As for being a 'pet', it could be a really odd or creative interpretation where the writer focuses on his relationship with his owl Hedwig in a very extreme way. But these are not typical views and are more of the result of some very out - of - the - box fanfiction ideas.
The magic system in Harry Potter might be a reason. It has some similarities with the mysterious and unruly nature of fae magic in some fanfic ideas. For example, magic in the wizarding world can sometimes be unpredictable, like fae magic.
In Harry Potter fanfiction, 'the red dragon' could be a lot of things. It might be a magical creature that the author has created or incorporated into their story. It could be a symbol, perhaps representing power, danger, or mystery within the fan - made plot.