No, Hogwarts is a building, not a sentient being with the ability to read in the traditional sense. It has magic and a kind of awareness, but not in a way that it can pick up a fanfiction and read it.
In the wizarding world, Hogwarts doesn't have the physical or mental capacity to read fanfiction. Fanfiction is a Muggle concept, and Hogwarts is a magical institution. Even if we consider its magic, it is more about protecting students, teaching magic, and maintaining the balance of the wizarding world, not about reading fictional stories about one of its students' deaths.
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.
There would be shock and disbelief. The wizarding world has always seen Hogwarts as a symbol of hope, knowledge and safety. If Harry destroys it, many would be in denial at first, thinking it couldn't be true. Wizards and witches from all over would come to the ruins, trying to figure out what had happened.
It could be that Hogwarts is trying to keep track of the cultural impact of the Harry Potter series. Fanfiction is a big part of the fandom culture, and Harry's death is a very significant event in the original story. By observing how fans handle this event in their own fictional works, Hogwarts (again, conceptually) can better understand the evolving relationship between the official story and the fan - created content.
One reason could be that he values the authenticity of the wizarding world he lived in, and fanfiction often strays from that.
Their view could become more confused. Fanfiction can present all sorts of alternate universes and character developments. The Death Eaters, used to a very specific view of the wizarding world under Voldemort, would find it hard to accept different versions. They might see the wizarding world in fanfiction as a chaotic and wrong place, which would make them double down on their own views to feel more secure.
The wizarding world would be in chaos. Voldemort might not be as threatened as he was with Harry around. The prophecy about Harry being the one to defeat Voldemort would be nullified, and the dark forces could gain more power. Hogwarts itself might lose some of its hope and protection as Harry was seen as a symbol of the future in the fight against the dark arts.
It would cause great shock. Harry was seen as a symbol of hope even before he started at Hogwarts. His death could lead to increased fear among the wizarding community as they might think Voldemort or other dark forces are getting stronger. It could also lead to a decline in the morale of those fighting against the dark side.
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.
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.
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.