One possible reason could be extreme anger. If something really bad happened to his loved ones, like if Voldemort came back in a different way and killed all his friends and family this time, Harry might be driven to the edge and decide to destroy the wizarding world that couldn't protect them.
Another reason might be a false sense of justice. He could be misled by some false information or an evil character. For example, if a character convinces him that the only way to end all the discrimination and inequality in the wizarding world is to destroy it and start anew, he might believe it and act accordingly. He might think that by destroying the current power - hungry and corrupt system, a better wizarding world can be built from the ashes.
Maybe in the fanfic, Harry is under the influence of a powerful dark object. This object could be warping his mind and making him see the wizarding world as something that needs to be destroyed. It could be whispering to him all the wrong ideas, making him believe that the world is beyond saving through normal means, so destruction is the only option.
One possible reason could be the trauma he has faced. Harry has endured a great deal of pain, from the loss of his parents to the constant battles and threats in the wizarding world. He might want to escape all that and find peace away from it.
It could be that in the fanfic, Harry Potter discovers some deep - seated secrets about the wizarding world's power structure. Feeling betrayed, he decides to take extreme actions to expose and destroy it. For example, if he finds out that the Ministry of Magic has been using unethical means to control the wizarding population, he might use his influence and magic to bring it all crashing down. He could start by revealing the truth to the public, which could lead to chaos and the destruction of the established order in the wizarding world.
One possible reason could be that he's tired of the constant danger and politics in the wizarding world. After all he's been through so much. He might just want a normal, quiet life away from magic.
One reason could be his over - use of powerful magic spells. If he uses spells like the 'Geminio' spell (used to duplicate objects) on valuable items without any control, it could flood the market and make the items worthless, thus ruining the economy. For example, if he duplicates rare magical potions in large quantities, the potion - making industry would collapse as there would be no need to buy them at regular prices.
One reason could be disillusionment. Maybe he discovers that the wizarding world is not as noble as he once thought, with a lot of hidden political intrigue and corruption. For example, the Ministry of Magic might be misusing its power, and Harry, being a symbol of justice, can't stand it anymore.
In some cases, he could be leaving in search of a greater purpose. He might feel that there are things he can learn or achieve outside the wizarding world that will ultimately help the wizarding community more. He may also leave because of some prophetic vision or a feeling that he doesn't belong there anymore, that his path lies elsewhere, away from the familiar magical realm he grew up in.
Well, in the traditional sense of the wizarding world of Harry Potter, it seems quite out of place. Wizards rely on magic, not mechanical constructs. However, if we consider a fanfiction scenario, anything can happen. Maybe Harry discovers some ancient magic that allows him to combine magic with technology in a way that enables him to build a mech. It could be a mech that uses magic as its power source, with spells inscribed on its parts for various functions.
One reason could be that he's tired of the constant danger and battles. After all he's been through, he might just want a normal, peaceful life away from magic. Maybe he wants to start a family in the Muggle world where his kids can grow up without the threat of dark wizards.
Sure. Although the wizarding world has its own rich literature, there's no reason to think that Harry couldn't be exposed to Matilda fanfiction. Wizards do have some knowledge of the Muggle world, and with the right connections or by accident, Harry could find himself reading it. He might be curious about the different kind of magic, or rather the extraordinary abilities in Matilda's story that are presented in a non - wizarding way.
Yes, it is possible. The wizarding world has libraries and secret places where he could potentially find fanfiction. There might be magical means of accessing stories written by fans, perhaps through enchanted books or parchment.