No, it's not common. Usually, fanfiction focuses on positive relationships between characters, especially Harry and the Weasleys who are often portrayed as a close - knit family. So this would be a rather unusual and dark theme.
Probably not. Given that the Weasleys are beloved characters in the Harry Potter universe, a fanfiction with such a negative and extreme concept as Harry destroying them is likely to be off - putting to a large number of fans. Fans usually look for fanfictions that expand on the positive aspects of the story, like friendships and adventures, rather than something so dark and against the norm.
I'm not sure about the specific plot of this fanfiction as it sounds rather unorthodox. It could be a very dark or alternate - universe take on the Harry Potter world where Harry goes against the Weasleys for some extreme reason.
It could mean that in this fanfiction, Harry is in a situation where he somehow causes harm or destruction to the Weasley family. Maybe he's under some dark influence or there's a big misunderstanding that leads to him acting against the Weasleys.
One possible reason could be that Harry has post - war trauma. He might have seen so much death and destruction during the war that he doesn't want to bring his darkness and pain to the Weasleys. He may think that staying away is a way to protect them from his own emotional turmoil.
At first, the Weasleys might try to reach out to Harry. But as he continues to avoid them, they could start to feel rejected. This might lead to some resentment building up, especially among the younger Weasleys who don't understand why Harry is acting this way. For example, Ron might be really frustrated as he considered Harry one of his best friends.
I'm not sure if it's a popular fanfiction. It's such a dark and against - the - grain concept for the 'Harry Potter' fandom that it might not have a large following. Most fans are used to the positive relationships between Harry and the Weasleys in the original series.
I haven't actually read this specific fanfiction, but it's a very dark and disturbing concept. In the normal 'Harry Potter' universe, Harry and the Weasleys are friends. So this fanfiction probably involves some sort of dark plot twist or alternate reality where Harry turns against them for reasons that could range from being influenced by dark magic to some misinterpreted prophecy or a huge misunderstanding.
In this fanfiction, the betrayal might also stem from jealousy. Harry is often in the spotlight, and the Weasleys, who have always been a big family but not always in the center of attention, could let envy get the better of them. This could lead to actions that Harry perceives as betrayal, like spreading rumors or withholding support when he needs it most.